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Benitoite

Benitoite

Douglas Sterrett’s 1911 USGS report on the mineral’s discovery, geology, mining, and properties.

faceted benitoite

Faceted benitoite: Five tiny gemstones of faceted benitoite in a color gradient set from nearly colorless to violetish-blue. Each stone is a round brilliant of about 3.5 millimeters and weighing about .20 carat. Photo by TheGemTrader.com.

benitoite crystals with neptunite crystals

Benitoite and neptunite crystals: This specimen is a plate of translucent blue benitoite crystals and black neptunite crystals on a background of white natrolite. (This association is typical and an important characteristic of the mineral.) The crystals are about 2 centimeters in length and the plate measures about 15 x 11 x 2 centimeters in size. The specimen is from the Dallas Gem Mine, San Benito River headwaters area, New Idria District, Diablo Range, San Benito County, California. Specimen and photo by Arkenstone / www.iRocks.com.

Information Sources
[1] Douglas B. Sterrett (1911). Benitoite, Gems and Precious Stones, Mineral Resources of the United States, Calendar Year 1909, Part II Nonmetals, pages 742-748, published 1911.

Description of Benitoite

An excellent description of the new California gem mineral, benitoite, has recently been given by G. D. Louderback, of the University of California. The locality was visited during the summer of 1909 by the present writer, and every facility was given for the examination of the deposit by the Dallas Mining Company through the kindness of Mr. Thomas Hayes, at that time acting superintendent. The following description has been abstracted in part from Doctor Louderback’s report and notes supplied from personal observation have been added.

Who Discovered Benitoite?

The difficulty mentioned by Doctor Louderback in learning who was the original discoverer of the benitoite property was encountered by the writer. It is evident that J. M. Couch, of Coalinga, grubstaked by R. W. Dallas, was instrumental in finding the deposit. Whether he discovered it while out alone or on a second trip with L. B. Hawkins, of Los Angeles, is a point in dispute. Material taken to Los Angeles by Mr. Hawkins was pronounced volcanic glass and valueless. According to Mr. Couch, specimens given to Harry U. Maxfield, of Fresno, were shown to G. Eacret, of Shreve & Co., San Francisco, and to G. D. Louderback. Specimens cut by Mr. Eacret were thought to be sapphire. Doctor Louderback found the material to be a new mineral and named it benitoite after the county in which it was found.

map of San Benito County

Benitoite mine map: Map showing the location in San Benito County in central California.

Location of the Benitoite Deposit

The benitoite mine is in the southeastern part of San Benito County, near the Fresno County line. The deposit is about 35 miles by road northwest of Coalinga in the Diablo Range, about three-fourths of a mile south of Santa Rita Peak, and on one of the tributaries of San Benito River. The elevation of the mine is about 4,800 feet above sea level; the elevation of Santa Rita Peak is 5,161 feet. The mine is in the end of one of the branching ridges from the south side of Santa Rita Peak. The end of the southward extension of this ridge is a low knob about 160 feet above the creek. This knob is called the apex, and from it a small spur extends to the west down to the creek. The benitoite mine is in the south side of this spur, about 50 feet lower than the apex and 250 feet west of it.

Geology of the Benitoite Deposit

The benitoite deposit occurs in a large area of serpentinewhich extends many miles northward past the New Idria quicksilver mine and a few miles southward, and forms the summit of an anticlinal ridge pitching down to Coalinga. This serpentine is of the usual type of the Coast Ranges and presents different phases from hard dark-green and greenish-black material to softer lighter-colored rock containing more or less talcose and chloritic minerals. Slickenside seams and lentil-shaped blocks and masses are common through the serpentine, much of which is decomposed near the surface and breaks down to light grayish-green soil which has a greasy feeling when rubbed between the fingers. Inclusions of masses of schists and other rocks of the Franciscan formation occur in the serpentine. These schists may be micaceous or more basic, having common hornblende, actinolite, or glaucophane as characteristic minerals.

The benitoite deposit is located in one of these basic inclusions, a portion of which has a somewhat schistose structure, while the rest is nearly massive. These phases were probably originally different adjacent formations that have been metamorphosed. Part of the massive form is a dark-gray to greenish-gray rock that might be called trap. In some specimens the following minerals are determinable under the microscope: augite, plagioclase crushed and recrystallized and containing clinozoisite prisms, secondary albite, yellow serpentine, and a little titanite and pyrite. The rock is therefore a partly metamorphosed diabase or gabbro. The more schistose phases are grayish-blue to blue and grade into vein material. They are composed of one or more varieties of hornblende, some partially chloritized, with albite, and, near the vein, with natrolite. The hornblende occurs in minute needles, felted masses of needles, blades, and stouter prisms. These have a bluish to yellowish green to nearly colorless pleochroism, and are in part probably actinolite and in part glaucophane or allied hornblende. The natrolite fails and the albite is also less abundant in the hornblende rock at some distance from the vein.

The vein is a highly mineralized shattered zone in the schistose rock. The fractures and joints with the vein filling are about parallel with the schistosity of the rock, which averages nearly east and west in strike with local variations and has a varying dip of 20° to 70° N. A sketch map of a small area on the benitoite mine hill giving the outcrops with their dips and strikes and the formations encountered in the mine workings shows the schist and gabbro inclusion in the serpentine to be quite irregular in shape. The width at the mine between the serpentine walls is about 150 feet and at a distance of 150 feet east of the mine it is only about 90 feet; about 80 feet farther east at the apex it is over 100 feet. This schist inclusion has been described by Kalph Arnold as 150 feet wide at its widest point and at least 1,200 feet long.

The metamorphism of the schist inclusion has been of two kinds — first mashing and sheeting of the original basic rock producing schistosity and opening channels for solutions and then a passage of mineral-bearing solutions recrystallizing and replacing the minerals of the rock with albite. The albite permeated the rock for many feet each side of the fracture zone. The conditions of temperature or pressure of the solutions became changed, so that natrolite was next deposited. The natrolite did not permeate far into the rock, but formed a coating on the walls of the fissures. Neptunite and benitoite were formed with the natrolite at this stage in the fissures and openings but did not penetrate the wall rock. This whole mineralized zone containing many bands and masses of natrolite with gem minerals in the joints, fissures, and open spaces in the brecciated hornblende rock may be called the vein.

The unfilled cavities and seams in the vein zone aided by later fractures and faults has offered an easy passage for more recent decomposing meteoric waters. The latter have leached portions of hornblende schist along and included in the vein, have removed part of the minerals of the vein, and have stained the natrolite on the walls of the cavities and seams with iron and manganese oxides. The rock, leached of albite, has a more or less porous texture and is composed principally of fine fibrous blue hornblende and actinolite.

benitoite crystal structure

Benitoite crystal structure: Crystal structure of benitoite, BaTiSi3O9, P-6c2, projected onto the (a,c) plane. Public domain image by Perditax.

Development of the Benitoite Mine

Development work at the benitoite mine at the time of the writer’s visit consisted of a large and a small open cut, a prospect drift or tunnel with a crosscut tunnel, and an incline shaft. The large open cut or “glory hole” was 20 to 45 feet wide, 85 feet long, and from a few feet to 35 feet deep; it had a north of east direction into the hillside. The smaller open cut was to the north side of the entrance of the larger cut and at a lower level, it was about 60 feet long and 10 to 15 feet deep. The prospect tunnel was driven 120 feet in a direction N. 70° E. from the end of the large open cut. The crosscut tunnel was 45 feet long and driven to the north at a right angle from the main tunnel at a distance of 50 feet from the mouth. The incline shaft was sunk 35 feet deep from the north side of the open cut at about the middle.

The prospect tunnel cut through the hornblende schist formation into decomposed serpentine. The contact was evidently a fault line, and near it the serpentine contained much talcose and scaly asbestiform material. The fault was directly across the schistosity with a north-south strike and a. dip of 45° W. This prospect tunnel encountered a little natrolite (vein material) in the hornblende schist in its upper west side, 15 feet beyond the crosscut tunnel, which crossed a small streak of vein material containing a little benitoite about 10 feet from the main tunnel. Vein material formed the roof of the prospect tunnel for several feet near its mouth. The “glory hole” was excavated in a very large pocket or bulge in the vein, a portion of which may still be seen along the north wall of the open cut. The incline shaft was apparently sunk in the lower part of this outcrop and did not encounter benitoite. The smaller open cut exposed vein material with benitoite, which was more plentiful near the east end of the cut than at the west end. The vein and the schist in this cut were much blackened and stained with films and seams of manganese dioxide. About 30 feet S. 60° E. of the upper end of the huge open cut a ledge of altered blue hornblende schist outcrops prominently. This ledge also carries a streak of natrolite with benitoite. Benitoite has been found in bowlders a few hundred yards west of the mine on the hillside and in the creek. These bowlders have evidently rolled from the outcrop on the hill above and probably from near the mine. Doctor Louderback states that benitoite lias been found for a distance of about 230 feet at the surface along the mineral zone and in very small quantity at its extremes. The writer observed benitoite in place through a distance of about 170 feet in an east and west direction.

The strike of the ledge outcropping to the east of the open cut was about N. 60° W., with a high northerly dip. The strike encountered in the tunnel, about 30 feet lower and to the north, was nearly cast and west with a dip of about 40° N. In the upper part of the face of the open cut the dip was high, about 65° N., and below the middle of the face it was low, 15° to 25° N. Along the north side of the open cut and in the lower cut the strike was about east and west and the dip was probably rather low, 20° to 30° N. These measurements do not agree closely with those of Doctor Louderback, especially in regard to the dip of the vein. Jointing of the rock and the irregular nature of the vein, however, make accurate measurements difficult. Doctor Louderback places the dip at 65° to 69° N., but the dip measured by the writer is much lower, probably 15° to 30° N. in the lower part of the cut. The evidence for this measurement is found in the position of the vein at the outcrop and in the tunnel, of the layers of blue schist and natrolite in the end of the cut, and of the ledge along the north side of the open cut and in the lower cut. Such a low dip would account for the failure of the incline to cut the mineralized zone. The failure might also be due to the pinching out of the vein a short distance below the large pocket opened in the “glory hole.” The impression gained by a study of the deposit and by plotting the location of the vein where encountered in different places was that the deposit consists of an ore shoot pitching to the west and lying in a fracture zone in hornblende schist with an irregular east and west strike and north dip. This shoot had a lenticular cross section with a thickness of more than 25 feet in the thickest part but pinching out on the sides. The upper edge of the shoot has been removed by erosion. A portion of the lover edge was encountered in the tunnel. The eastern extension of such a shoot would have been removed by erosion and the western extension would be underground, to the north of, west of, and below, the open cut.

Doctor Louderback mentions the outcrop of spheroidal gabbro on the southeast of the benitoite deposit on the hillside. The outcrop of rock on the north side of the vein zone, on the summit of the ridge, is of a similar nature and has been mentioned above as diabase or gabbro. The same rock was encountered in the crosscut tunnel 40 feet below the surface and 30 feet north of the main tunnel. Underground this rock occurred in large loose spheroidal bowlders ranging up to several feet in thickness, with large openings between them. This material was difficult to mine and required careful timbering. The open spaces evidently extended to the surface above, as a strong draft of air came through them. The spheroidal shape of the blocks and the open spaces between them were doubtless formed by decomposition and leaching along fracture planes.

benitoite crystals showing fluorescence

Fluorescent benitoite: This is a photograph of small benitoite crystals under ultraviolet light. The mineral exhibits a brilliant blue color under ultraviolet radiation. Public domain photo by Parent Géry.

Mineralogy of the Benitoite Zone

The benitoite occurs with neptunite in crusts, seams, and thicker deposits of white natrolite on the walls of geode-like cavities and fissures in the hornblende schist. These deposits occur in both irregularly shaped masses and in seams with more definite directions. They inclose fragments of hornblende schist which has been heavily impregnated with natrolite. In some of the inclusions the gradation from the hornblende rock containing much natrolite to natrolite containing acicular inclusions of hornblende is complete. The benitoite is embedded in or attached to natrolite, being in some places completely, in other places partly, enveloped by it. In the latter places the benitoite projects into the cavities along with the coarse drusy surfaces of the natrolite. Natrolite with or without benitoite and neptunite fills some of the fissures and former cavities completely. The benitoite is always in contact with natrolite and has not been found embedded in the hornblende rock alone. It is in many places attached to hornblende impregnated with natrolite and is partly or completely inclosed in natrolite on the remaining sides. The neptunite is subject to the same relations with the natrolite and is, in places, partly surrounded by benitoite. These facts point to the same period of formation for the three minerals with the power of crystallization arranged in the following order: neptunite, benitoite, and natrolite.

Obtaining Benitoite Specimens

The benitoite is obtained by breaking open masses of vein rock and carefully chiseling or working the crystals out of the inclosing natrolite. Many gems are injured or ruined by this method. The removal of the natrolite by acid has been tried with partial success. Large slabs of rock 2 to 3 or more feet across are obtained coated with natrolite and carrying benitoite and neptunite. The last two minerals are either visible on the drusy surface of the natrolite or are completely covered by natrolite. The position of the benitoite and neptunite is often marked by lumps or a thickening of the natrolite crust. By carefully cutting into these lumps beautiful crystals are sometimes uncovered. Often the inclosing crust or shell of white natrolite can be split from a crystal of neptunite or benitoite in two or three large pieces, so that the covering can readily be replaced over the crystal. Such material makes beautiful specimens. Slabs of bluish hornblende rock with a drusy pure white crust of natrolite containing brilliant reddish-black neptunite and blue benitoite in fine crystals are excellent for the same purpose.

The minerals associated with benitoite are described and analyses are given in the paper of Louderback and Blasdale. Neptunite is titanium silicate containing iron, manganese, potassium, sodium, and magnesium. It occurs in black to reddish- black prismatic crystals of the monoclinic system, the length commonly being several times the thickness. It has a prismatic cleavage and the thin splinters or powder show a deep reddish-brown color. The hardness is between 5 and 6 and the specific gravity 3.18 to 3.19. Neptunite is practically insoluble in hydrochloric acid.

The natrolite, with which the benitoite and neptunite are associated, does not generally occur in distinct crystals of any size. It forms massive granular white aggregates of crystallized material with curved ridge-like or cockscomb-like groups of crystals and drusy botryoidal masses in the cavities. Natrolite is a hydrous silicate of sodium and aluminum crystallizing in the orthorhombic system.

Other minerals occurring in smaller quantity in the cavities are emerald-green copper stain, amphibole needles, albite, aegirine, and psilomelane. The amphiboles are actinolite, a variety intermediate between crossite and crocidolite, and a little glaucophane.

Physical Properties of Benitoite
Chemical Classification Barium Titanium Silicate
Color Most specimens are violetish-blue. Some specimens are colorless. A range of color and saturation between colorless and deep violetish-blue occurs. Rare orange heat-treated specimens are known.
Streak White
Luster Vitreous
Diaphaneity Transparent to translucent
Cleavage Poor
Mohs Hardness 6 to 6.5
Specific Gravity 3.6
Diagnostic Properties Tabular dipyramidal crystals. Intense blue fluorescence under short-wave ultraviolet light. Associated with serpentine and albite, but more importantly with rare minerals such as natrolite, joaquinite, and neptunite.
Chemical Composition BaTiSi3O9
Crystal System Hexagonal
Uses Gemstone, collector mineral, Official State Gem of California.

Chemical and Physical Properties of Benitoite

The chemical and physical properties of benitoite and its associated minerals have been described by Louderback and Blasdale, and the following notes are taken from their description. The chemical analyses show it to be an acid barium titano-silicate corresponding to the formula BaTiSi3O9 . Benitoite is insoluble in ordinary acids, but is attacked by hydrofluoric acid and dissolves in fused sodium carbonate. Alone, it fuses quietly to a transparent glass at about 3. The color of benitoite is not affected by heating the stone to redness and allowing to cool. The hardness is greater than orthoclase and less than peridot, or about 6 to 6 1/2, and the specific gravity is 3.64 to 3.67.

Benitoite crystallizes in the trigonal division of the hexagonal system. The common forms observed are the base c(0001), trigonal prisms m(1010), and n(0110), and the trigonal pyramids p(1011) and π(0111). Other forms are rather rare and of small importance. Of these faces the pyramid π generally has the largest development. This gives the crystal a triangular aspect with the corners truncated by smaller planes. The prism faces are narrow, though generally present. Many of the crystals are naturally etched on one or more sets of faces. Such faces are a little dulled or slightly pitted. Benitoite has an imperfect pyramidal cleavage and a conchoidal fracture.

faceted benitoite

Faceted benitoite: Three blue stones of faceted benitoite. Benitoite is often cut into round brilliants because of its high refractive index and dispersion. Cutters must orient benitoite carefully to take full advantage of its pleochroism. Photo by TheGemTrader.com.

Benitoite Gemology

The mean refractive index of benitoite is greater than that of sapphire, and measures 1.757 to 1.804 (sapphire 1.759 to 1.767). The birefringence is high and the pleochroism very strong. The crystals are generally transparent with a pale to deep-blue and bluish-violet color. Color variations are common in the same crystal, and the change from dark to light blue or colorless may be sharp or gradual. The pleochroism of benitoite is pale to dark-blue or purplish and colorless. The richest colors are seen when the crystals are viewed parallel to the base. The intensity of the blue diminishes as the light ray penetrates the crystal at other angles until perpendicular to the base, when the crystal is colorless. Care is necessary, therefore, in cutting the gem so as to secure the best effects. Pale-colored stones should be cut with the table perpendicular to the base or parallel to the vertical axis of the crystal to secure the full color value. Deeper colored stones may be cut in the same way or with the table in an intermediate position, if the color is very strong. By cutting intensely colored stones with the table only slightly out of parallel to the base, the color may be reduced to a desirable shade. The dichroscope may be used to determine the position of the vertical axis and accordingly of the base perpendicular to it. When viewed perpendicular to the vertical axis with a dichroscope the twin colors or two rays of light are very intense to pale blue (depending on the depth of color of the crystal) and colorless. When viewed parallel to the vertical axis, or perpendicular to the base, the two rays are colorless and remain so while the dichroscope is rotated. The color of one of the rays becomes stronger as the crystal is rotated from this position. Benitoite crystals exhibiting two shades of color, as dark and light blue or blue and colorless in different parts of the same crystal, may be cut so as to show these variations, or sometimes in such, a way that the resulting color is of nearly uniform intensity.

Benitoite has been cut as a brilliant, with the step or trap cut, and “en cabochon.” The brilliant cut is especially suitable to show the brilliancy and fire of the gem. The brilliancy is due to the high refractive index and the fire or red flash, often seen in dull or artificial light is, in part at least, caused by the dispersion of the mineral. Of the colors produced by dispersion during the refraction of light in benitoite yellow and green are largely absorbed in the colored gems so that principally red and violet-colored lights are seen. These flashes of colored lights along with the natural fine blue of benitoite render the gem particularly beautiful. The step cut displays the color of benitoite to advantage, with only slight loss of brilliancy. Cabochon-cut gems from crystals with color variations or partially flawed material have some beauty.

The size of the gems cut from benitoite range in weight from a small fraction of a carat to several carats. According to Doctor Louderback the largest perfect stone so far cut weighs over 7 carats and is about three times as heavy as the next largest flawless gem so far obtained. The majority of larger cut stones weigh from 1 1/2 to 2 carats.

The principal production is in stones weighing less than 1 1/2 carats. The use of benitoite in rings or jewelry subjected to hard wear is limited by its comparative softness. The beautiful color, brilliancy, and fire of the gem, however, adapt it to other classes of fine jewelry. Since the supply of benitoite is thought to be limited and a fairly large demand has already arisen for the gem, it is probable the price will be kept high, possibly as high as that of sapphire, its nearest rival in color.

Other Benitoite Deposits?

So far benitoite has been found at one place only. J. M. Couch, one of the original discoverers of the benitoite deposit, has located several prospects in formations resembling that at the benitoite mine. In one of these, three-fourths of a mile to the north on the east side of Santa Rita Peak, cavities lined with natrolite crusts and crystals have been found in a bluish hornblende schist rock very similar to that at the original mine. The schist near the vein is composed of bluish hornblende and actinolite needles penetrating granular masses of albite. This rock also incloses crystals of natrolite showing that part of it was formed later than or during the crystallization of the natrolite. In the cavities the natrolite occurs in simple well-developed white columnar crystals up to a centimeter or more in thickness and several times as long. Neither benitoite nor neptunite have been found associated with this natrolite.

http://geology.com/gemstones/benitoite/

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The History Of Beads – 20 Fascinating Facts!

The History Of Beads – 20 Fascinating Facts!

 Published: 6th May, 2016 by Boundless Beads

The History Of Beads – 20 Fascinating Facts!

We tend to think of decorative jewellery as a relatively recent phenomenon. In fact, archaeological evidence suggests that early humans may have created and worn beaded jewellery up to 75,000 years ago, making it one of the world’s oldest expressions of individuality and status.

Did you know?

  1. Two beads made from ostrich eggshell were discovered by archaeologists in Tanzania in 2004, and are thought to be around 70,000 years old. They are believed to be the world’s earliest known beaded jewellery.
  2. The discovery of beads of this age is significant because they provide evidence that early homo sapiens were capable of ‘symbolic thinking’. Whether for trade, or to demonstrate status or identity, archaeologists believe these early beads had little to do with survival.
  3. The earliest known European beads date from around 38,000 BC, and were discovered at La Quina in France. The beads – made from grooved animal teeth and bones – were probably worn as pendants, and represent a time when homo sapiens were replacing Neanderthals and living more complex lives.
  4. As homo sapiens evolved, the implementation of farming and the accumulation of material possessions acted as stimuli to trade. An unprecedented level of craftsmanship developed, including weaving, pottery and bead-making in various forms.
  5. As long-distance trading grew, it encouraged the exchange of culturally significant artefacts. Beads became a popular commodity due to the ease with which they could be carried. Agate, serpentine, Sinai turquoise and cowrie shells from the Mediterranean, as well as coral and carnelian, were some of the first beads traded and have been discovered at archaeological sites throughout the Middle East.
  6. From around 6,000 BC, beads and their raw materials became an increasingly significant ‘currency’. Lapis lazuli beads – which were mined 1,500 miles away in Afghanistan – were of great importance to the Sumerians of southern Mesopotamia. Often, it was the raw materials that were traded, with the beads themselves fashioned locally to fulfil cultural need.
  7. During the Bronze Age, Greek traders from Mycenae established strong trade links with less advanced cultures around the Baltic. Copper and bronze was exchanged for amber, with was then fashioned into beads. The Greek traders also passed on cultural knowledge and expertise which helped the Baltic communities to advance.
  8. The first known glass-type beads were Egyptian faience beads which were made from clay, but had a thin lustrous glass-type (vitreous) coating. From about 5,000 – 2,000 years ago (a period of remarkable stability in Egypt), Egyptian bead-makers often worked under the patronage of kings or priests. They used sophisticated techniques and an incredible variety of precious materials to create stunning beaded jewellery which was worn as an expression of status and hierarchy.
  9. More complex glass beads, such as mosaic or ‘millefiori’ beads, were developed in Mesopotamia about 3,500 years ago. Further refined by the Syrians and Egyptians, these sophisticated beads were traded as far north as Scandinavia. As these empires fell, the expert bead-workers – whether by their own volition or by force – would relocate, taking their skills and secrets with them.
  10. The Romans, who had a love of coloured translucent glass, created sophisticated new kilns to produce more liquid-type glass. They developed glass drawing and glass blowing techniques, and drew on the knowledge of their best bead-workers, many of whom hailed from the eastern provinces. They traded large numbers of glass beads (in a myriad of colours and sizes). Roman beads have been found as far east as China and Korea, as well as north to Scandinavia, and south to Mali and Ethiopia, these beads were traded through new and existing trading routes often passing through many different cultures.
  11. Often, the Romans traded beads for profit with less technologically-advanced cultures. They also traded beads in exchange for local resources, such as Whitby Jet and Baltic Amber, which were available at the extremes of the Roman Empire.
  12. As the production capacity of the Roman glass manufactures increased, beads were no longer produced for just the elite, but for the general public too, although the bead quality was often poorer.
  13. With the collapse of the Roman Empire, so the glass-making expertise dispersed and regional bead styles evolved. Previously settled tribes began to migrate, taking highly-sophisticated bead jewellery with them as a portable form of wealth.
  14. European glass bead production diminished during the medieval period, apart from in small pockets of France, Italy and Germany, where imported soda used in the glass production process, was replaced with potash lime made from local wood ash.
  15. By the early fifteenth century, Venice became the glass and bead making centre of Europe, (lesser centres also existed in Holland, Bohemia and Moravia) due largely to tribal conquests in the Middle East ending 3,000 years of bead production. There is speculation that after the Ottomans captured Constantinople in 1453, many of the glass makers there moved to Venice, taking their secrets with them.
  16. Venetian glass bead production was concentrated on the island of Murano (which was by now the world’s dominant bead production centre) to protect the city from fire risk from the kilns, and to safeguard the production secrets of the glass workers.
  17. In 1797, Venice fell to Napoleon. Many of the city’s bead and glassworkers were taken to France where their secret production techniques were uncovered. This allowed for the growth of new European bead production centres in the Czech Republic and Holland.
  18. From about 1750, beads from the Bohemian region of the Czech Republic became a viable alternative to Venetian beads. As the Venetian bead empire faltered, so the Bohemians began to develop unique production techniques, which – from about 1737 – included the cutting of glass on water powered cutting wheels. Two distinct forms of ‘Kristallerie’ cutting evolved; ‘Kugeln’ (globe) cutting which used a vertical cutting wheel to produce a concave cut, and ‘Englisch-Schliff’(English Cut) horizontal wheels which produced a flat cut. By 1829 there were 152 specialist cutting workshops in Gablonz (Jablonec nad Nisou) alone, as well as more than a thousand local ‘cottage’ producers.
  19. The world famous Daniel Swarovski was born into a glass cutting family in northern Bohemia in 1862. In 1883, Swarovski attended the ‘First Electricity Exhibition’ in Vienna, which inspired him to improve methods of cutting and faceting glass beads. In 1892, Swarovski patented the first electric glass cutting machine, leading to the birth of the mechanised production of crystal glass.
  20. Following the end of the Second World War, the sudden expulsion of the ‘Sudeten German’ element of Bohemia (some three million people), brought an end to many of the region’s famous glass and jewellery making dynasties. Under a new communist Russian regime, an alternative Bohemian glass bead culture – fuelled by creative Czech artists – began to grow and still exists today. For many years, the state run export house Jablonex, controlled a large portion of Bohemia’s glass industry. In 2009, the region’s core glass production business passed to the Preciosa Group, who continue to uphold the traditions of Czech glass production, and whose beads are still, to this day, primarily made from drawn glass rods

About Boundless Beads

Established in 1992, we are a UK-based, family-run business. We supply exquisite artisan beads and beautiful hand-crafted jewellery elements to the hobbyist market and to wholesale partners throughout the UK and globally.We are privileged to work closely with some of the industry’s best glassworkers and bead-makers, many of whom hail from the world-renowned Bohemian dynasties of the Czech Republic. Many of the beads we sell are entirely unique to our collections and can be found no-where else in the marketplace.

https://www.boundlessbeads.com/blog/post/the-history-of-beads-20-fascinating-facts/

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Bastnäsite

Bastnäsite

From Wikipedia, the free encyclopedia
Bastnäsite, bastnaesite
Bastnaesit Burundi.jpg

Bastnäsite from Burundi
General
Category Carbonate mineral
Formula
(repeating unit)		 (REE)CO3F
Strunz classification 5.BD.20a
Crystal system Hexagonal
Crystal class Ditrigonal dipyramidal (6m2)
H-M symbol: (6 m2)
Space group P62c
Unit cell a = 7.118(1) Å,
c = 9.762(1) Å; Z = 6
(bastnäsite-(Ce))
Identification
Color Honey-yellow, reddish brown
Crystal habit Tabular to equant striated crystals, also granular, massive
Twinning Dauphine law, Brazil law and Japan law
Cleavage Imperfect to indistinct on {1010}, parting on {0001}
Fracture Uneven
Mohs scalehardness 4–5
Luster Vitreous, greasy, pearly on basal partings
Streak White
Diaphaneity Transparent to translucent
Specific gravity 4.95–5.0
Optical properties Uniaxial (+)
Refractive index nω = 1.717–1.722
nε = 1.818–1.823
Birefringence δ = 0.101 max.
Pleochroism Faint
Other characteristics Strongly piezoelectric; dark red cathodoluminescence
References [1][2][3]

The mineral bastnäsite (or bastnaesite) is one of a family of three carbonate–fluoride minerals, which includes bastnäsite-(Ce) with a formula of (Ce, La)CO3F, bastnäsite-(La) with a formula of (La, Ce)CO3F, and bastnäsite-(Y) with a formula of (Y, Ce)CO3F. Some of the bastnäsites contain OH− instead of F− and receive the name of hydroxylbastnasite. Most bastnäsite is bastnäsite-(Ce), and cerium is by far the most common of the rare earths in this class of minerals. Bastnäsite and the phosphate mineral monazite are the two largest sources of cerium and other rare-earth elements.

Bastnäsite was first described by the Swedish chemist Wilhelm Hisinger in 1838. It is named for the Bastnäs mine near Riddarhyttan, Västmanland, Sweden.[2] Bastnäsite also occurs as very high-quality specimens at the Zagi Mountains, Pakistan. Bastnäsite occurs in alkali granite and syenite and in associated pegmatites. It also occurs in carbonatites and in associated fenites and other metasomatites.[1][4]

Composition[edit]

Bastnäsite crystal from the Manitou District, El Paso County, Colorado, USA (size: 4.3×3.8×3.3 cm)

Bastnäsite has cerium, lanthanum and yttrium in its generalized formula but officially the mineral is divided into three minerals based on the predominant rare-earth element.[5] There is bastnäsite-(Ce) with a more accurate formula of (Ce, La)CO3F. There is also bastnäsite-(La) with a formula of (La, Ce)CO3F. And finally there is bastnäsite-(Y) with a formula of (Y, Ce)CO3F. There is little difference in the three in terms of physical properties and most bastnäsite is bastnäsite-(Ce). Cerium in most natural bastnäsites usually dominates the others. Bastnäsite and the phosphate mineral monazite are the two largest sources of cerium, an important industrial metal.

Crystal structure of bastnäsite-(Ce). Color code: carbon, C, blue-gray; fluorine, F, green; cerium, Ce, white; oxygen, O, red.

Bastnäsite is closely related to the mineral series parisite.[6] The two are both rare-earth fluorocarbonates, but parisite’s formula of Ca(Ce, La, Nd)2(CO3)3F2 contains calcium (and a small amount of neodymium) and a different ratio of constituent ions. Parisite could be viewed as a formula unit of calcite (CaCO3) added to two formula units of bastnäsite. In fact, the two have been shown to alter back and forth with the addition or loss of CaCO3 in natural environments.[citation needed]

Bastnäsite forms a series with the minerals hydroxylbastnäsite-(Ce) [(Ce,La)CO3(OH,F)] and hydroxylbastnäsite-(Nd).[7] The three are members of a substitution series that involves the possible substitution of fluoride (F−) ions with hydroxyl (OH−) ions.

Name[edit]

Bastnäsite crystal, Zagi Mountain, Federally Administered Tribal Areas, Pakistan. Size: 1.5×1.5×0.3 cm.

Bastnäsite gets its name from its type locality, the Bastnäs Mine, Riddarhyttan, Västmanland, Sweden.[8] Ore from the Bastnäs Mine led to the discovery of several new minerals and chemical elements by Swedish scientists such as Jöns Jakob Berzelius, Wilhelm Hisinger and Carl Gustav Mosander. Among these are the chemical elements cerium, which was described by Hisinger in 1803, and lanthanum in 1839. Hisinger, who was also the owner of the Bastnäs mine, chose to name one of the new minerals bastnäsit when it was first described by him in 1838.

Occurrence[edit]

Although a scarce mineral and never in great concentrations, it is one of the more common rare-earth carbonates. Bastnäsite has been found in karst bauxitedeposits in Hungary, Greece and the Balkans region. Also found in carbonatites, a rare carbonate igneous intrusive rock, at the Fen Complex, Norway; Bayan Obo, Mongolia; Kangankunde, Malawi; Kizilcaoren, Turkey and the Mountain Pass rare earth mine in California, US. At Mountain Pass, bastnäsite is the leading ore mineral. Some bastnäsite has been found in the unusual granites of the Langesundsfjord area, Norway; Kola Peninsula, Russia; Mont Saint-Hilaire mines, Ontario, and Thor Lake deposits, Northwest Territories, Canada. Hydrothermal sources have also been reported.

The formation of hydroxylbastnasite (NdCO3OH) can also occur via the crystallization of an rare-earth bearing amorphous precursor. With increasing temperature, the habit of NdCO3OH crystals changes progressively to more complex spherulitic or dendritic morphologies. The development of these crystal morphologies has been suggested [9] to be controlled by the level at which supersaturation is reached in the aqueous solution during the breakdown of the amorphous precursor. At higher temperature (e.g., 220 °C) and after rapid heating (e.g. < 1 h) the amorphous precursor breaks down rapidly and the fast supersaturation promotes spherulitic growth. At a lower temperature (e.g., 165 °C) and slow heating (100 min) the supersaturation levels are approached more slowly than required for spherulitic growth, and thus more regular triangular pyramidal shapes form.

Mining history[edit]

In 1949, the huge carbonatite-hosted bastnäsite deposit was discovered at Mountain Pass, San Bernardino County, California. This discovery alerted geologists to the existence of a whole new class of rare earth deposit: the rare earth containing carbonatite. Other examples were soon recognized, particularly in Africa and China. The exploitation of this deposit began in the mid-1960s after it had been purchased by Molycorp (Molybdenum Corporation of America). The lanthanide composition of the ore included 0.1% europium oxide, which was sorely needed by the burgeoning color television industry, to provide the red phosphor, so as to maximize picture brightness. The composition of the lanthanides was about 49% cerium, 33% lanthanum, 12% neodymium, and 5% praseodymium, with some samarium and gadolinium, or distinctly more lanthanum and less neodymium and heavies as compared to commercial monazite. However, the europium content was at least double that of a typical monazite. Mountain Pass bastnäsite was the world’s major source of lanthanides from the 1960s to the 1980s. Thereafter, China became increasingly important to world rare earth supply. Chinese deposits of bastnäsite include several in Sichuan Province, and the massive deposit at Bayan Obo, Inner Mongolia, which had been discovered early in the 20th century, but not exploited until much later. Bayan Obo is currently (2008) providing the majority of the world’s lanthanides. Bayan Obo bastnäsite occurs in association with monazite (plus enough magnetite to sustain one of the largest steel mills in China), and unlike carbonatite bastnäsites, is relatively closer to monazite lanthanide compositions, with the exception of its generous 0.2% content of europium.[citation needed]

Ore technology[edit]

At Mountain Pass, bastnäsite ore was finely ground, and subjected to flotation to separate the bulk of the bastnäsite from the accompanying barite, calcite, and dolomite. Marketable products include each of the major intermediates of the ore dressing process: flotation concentrate, acid-washed flotation concentrate, calcined acid washed bastnäsite, and finally a cerium concentrate, which was the insoluble residue left after the calcined bastnäsite had been leached with hydrochloric acid. The lanthanides that dissolved as a result of the acid treatment were subjected to solvent extraction, to capture the europium, and purify the other individual components of the ore. A further product included a lanthanide mix, depleted of much of the cerium, and essentially all of samarium and heavier lanthanides. The calcination of bastnäsite had driven off the carbon dioxide content, leaving an oxide-fluoride, in which the cerium content had become oxidized to the less basic quadrivalent state. However, the high temperature of the calcination gave less-reactive oxide, and the use of hydrochloric acid, which can cause reduction of quadrivalent cerium, led to an incomplete separation of cerium and the trivalent lanthanides. By contrast, in China, processing of bastnäsite, after concentration, starts with heating with sulfuric acid.[citation needed]

Extraction of rare-earth metals[edit]

Process flow diagram for pyrometallurgy extraction of rare-earth metals from bastnasite ore

Bastnäsite ore is typically used to produce rare-earth metals. The following steps and process flow diagram detail the rare-earth-metal extraction process from the ore.[10][11]

  1. After extraction, bastnasite ore is typically used in this process, with an average of 7% REO (rare-earth oxides).
  2. The ore goes through comminution using rod mills, ball mills, or autogenous mills.
  3. Steam is consistently used to condition the ground ore, along with soda ash fluosilicate, and usually Tail Oil C-30. This is done to coat the various types of rare earth metals with either flocculent, collectors, or modifiers for easier separation in the next step.
  4. Flotation using the previous chemicals to separate the gangue from the rare-earth metals.
  5. Concentrate the rare-earth metals and filter out large particles.
  6. Remove excess water by heating to ~100 °C.
  7. Add HCl to solution to reduce pH to < 5. This enables certain REM (rare-earth metals) to become soluble (Ce is an example).
  8. Oxidizing roast further concentrates the solution to approximately 85% REO. This is done at ~100 °C and higher if necessary.
  9. Enables solution to concentrate further and filters out large particles again.
  10. Reduction agents (based on area) are used to remove Ce as Ce carbonate or CeO2, typically.
  11. Solvents are added (solvent type and concentration based on area, availability, and cost) to help separate Eu, Sm, and Gd from La, Nd, and Pr.
  12. Reduction agents (based on area) are used to oxidize Eu, Sm, and Gd.
  13. Eu is precipitated and calcified.
  14. Gd is precipitated as an oxide.
  15. Sm is precipitated as an oxide.
  16. Solvent is recycled into step 11. Additional solvent is added based on concentration and purity.
  17. La separated from Nd, Pr, and SX.
  18. Nd and Pr separated. SX goes on for recovery and recycle.
  19. One way to collect La is adding HNO3, creating La(NO3)3. HNO3 typically added at a very high molarity (1–5 M), depending on La concentration and amount.
  20. Another method is to add HCl to La, creating LaCl3. HCl is added at 1 M to 5 M depending on La concentration.
  21. Solvent from La, Nd, and Pr separation is recycled to step 11.
  22. Nd is precipitated as an oxide product.
  23. Pr is precipitated as an oxide product.

https://en.wikipedia.org/wiki/Bastn%C3%A4site

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Azurite – Physical Properties & Healing Properties

Azurite – Physical Properties & Healing Properties 

Chemistry: Cu3(CO3)2(OH)2, Copper Carbonate Hydroxide

Class: Carbonates

Uses: Ornamental stone, pigment, minor ore of copper, and jewelry.

Click to view larger image
  • Azurite
  • Azurite Cubes
  • Azurite Crystal
  • Azurite Malachite

 

Azurite is a very popular mineral because of its unparalleled color, a deep blue called “azure”, hence its name. The color is due to the presence of copper (a strong coloring agent), and the way the copper chemically combines with the carbonate groups (CO3) and hydroxyls (OH).

At times its color is too deep and larger crystals can appear black. Small crystals and crusts show the lighter azure color well. Azurite is often associated with its colorful close cousin, malachite.

Green malachite is closely associated with azurite in many ways. Not only do they frequently occur together they also have very similar formulae. Malachite can also replace azurite, making a pseudo morph, or an exact copy of an azurite crystal (only now instead of being blue, it would be green).

It is also an unimportant ore of copper, although its significance has been more impressive in the past. It is still considered a minor ore of copper; mostly because it is found associated with other more valuable copper ores. Fine crystal clusters, nodular specimens, and interesting and beautiful combinations with malachite are important pieces in anyone’s mineral collection.

The magnificent color of azurite is worth mentioning again as it truly is a one-of-a-kind in the mineral world. Azurite is one of those classic minerals.

 

Azure is derived from the Arabic word for blue.

 

Azurite paints made centuries ago have undergone the transformation much to the imagined horror of artists whose paintings of beautiful blue skies now have a most unusual green hue! Thankfully for mineralogists and collectors, this transformation is one of the most aesthetically pleasing in the mineral kingdom.

Although the malachite may soften the sharpness of the azurite crystal, it generally leaves the specimen intact and a whole range of transformations from pure azurite to pure malachite can be obtained. There really is no comparison to any other mineral to mineral transformation in terms of overall beauty.

Azurite is a deep blue copper mineral produced by weathering of copper ore deposits that is soft in color and it frequently forms with the green mineral stone Malachite. Azurite is sometimes impregnated with a clear wax to enhance color and appearance yet it is mainly used to stabilize the stone. This is due to the fact that Azurite is a soft brittle stone and ammonia, acids and hot liquids can damage or dissolve it and can scratch easy.

 

 

Notable Occurrences include numerous localities worldwide, but special localities produce some outstanding specimens especially from Lasal, Utah; Bisbee, Arizona and New Mexico, USA; Mexico; Tsumeb, Nambia; Shaba, Congo; Toussit, Morocco; Australia and in many locations in Europe.

 

 

Azurite is used in jewelry. Azurite has been used as a dye for paints and fabrics for eons. Azurite was used as a blue pigment for centuries.

Depending on the degree of fineness to which it was ground, and its basic content of copper carbonate, it gave a wide range of blues.

Azurite is used occasionally as beads and as jewelry, and also as an ornamental stone. However, its softness and tendency to lose its deep blue color as it weathers limit such uses. Heating destroys azurite easily, so all mounting of azurite specimens must be done at room temperature.

 

Azurite is the stone that awaken psychic ability, insight and intuition. Azurite is called the “stone of heaven.” It aids in developing psychic awareness, psychic skills and abilities, enhancing intuition. Excellent for meditation. Brings just the right amount of energy to any situation. Professed to be helpful for healing in general, cancer prevention, liver issues arthritis, joint problems, depression, sinuses, skin problems. Azurite is most closely related to the third eye chakra, and can balance, stimulate, and empower it. It will also work to align all of the chakras. Azurite in combination with malachite is excellent for stress and anxiety relief.

No crystal embodies the pure Blue Ray quite like Azurite. The rich vibrancy of its dark-blue energy resonates to the exact frequency of the Third-Eye Chakra, and has been guiding souls to enlightenment since the earliest civilizations began. To the inhabitants of Atlantis and the early Egyptians, Azurite was a most potent psychic stone and shrouded in mystery; its secrets known only to the highest priests and priestesses. It was called the Stone of Heaven by the ancient Chinese who believed it to open celestial gateways, and was revered by Greeks and Romans for its visionary insights and healing powers. For the Mayans, Azurite inspired the mystical self and facilitated the transfer of wisdom and knowledge via thought, while Native Americans used this sacred stone to contact their spiritual Indian guide, feel the presence and understand the message.

It resonates within both the sacral chakra and the heart chakra to help you to recognize a loving attitude in others and will stimulate the same in yourself. Within your thymus chakra or higher heart…. it helps to bring through strong compassion and empathy for the circumstances of others.

 

Color: Azure, deep blue or pale blue if found in small crystals or crusts.

Luster: Vitreous to dull depending on habit.

Transparency: : Transparent if in thin crystals, otherwise translucent to opaque.

Crystal System: Monoclinic; 2/m.

Crystal Habits: Crystals are irregular blades with wedge shaped terminations. Also, aggregate crusts and radiating, botroyoidal, nodular and earthy masses.

Cleavage: Good in one direction and fair in another.

Fracture: Conchoidal and brittle.

Hardness: 3.5 – 4.

Specific Gravity: 3.7+ (heavier than average).

Streak: Blue.

Associated Minerals: Numerous and include malachite limonite, calcite, Cerussite, quartz, chalcopyrite, native copper, cuprite, chrysocolla, Aurichalcite, Shattuckite, liroconite, connellite and other oxidized copper minerals.

Best Field Indicators: Color, softness, crystal habits and associations.

http://www.kidzrocks.com/v/education/AZURITE

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Aventurine

Aventurine

Aventurine
Last updated : October 23, 2017 12:46 PM

The stone of opportunity, Aventurine is thought to be the luckiest of all the other crystals. It is great in manifesting wealth and prosperity and favours activities related to finances, like gambling, lotto, and lottery. It is also a belief amongst many experienced and experts that one should never go for buying lottery tickets without an Aventurine in the pocket.

Aventurine is also called as Avanturine, Adventurine, Indian Jade and Aventurine Quartz. It has many uses other than its metaphysical purposes, such as Aventurine is used in bowls, figurines, jewellery, vases, building stone, monuments, aquaria, etc. Stone that proffers opportunity in the life contemplates being the luckiest gem for the soul that is looking for attaining all the riches of the life. It is too noticeable for yielding the wealth and prosperity of all kind. Contemplate to be luckiest of all gemstones, it holds the propensity to attract riches and wealth that makes the life full of prosperity and joyous to live. The eminence of the stone is renowned among gamblers most as it helps them to win the chances of the game and bring affluence to their life. The resonating vibes of Aventurine drive profit to live a healthy and flourishing lifestyle.
Aside from attracting monetary opulence and success, it too proffers base for magnetizing new opportunities. It too invites the newness in life by letting go the old rules and patterns that make life static. The energies of the stone not only bring luck and riches to the life but too helps to let go the bad habits. The grounding energies of the stone helps to get closer to nature as well as feel the beauty of the gifted life. It furnish the forward-looking path in achieving the new heights and grow with the twists and turns of the life.
The tints of Aventurine too infuses the zest for living a gifted life and see the unseen paths of life enthusiastically. The proficiency of the Aventurine energies bestow a support to the soul to move ahead in the span of life without looking back and forgetting the traumas faced in the past. It too imparts courage to embrace the positive changes that hearten the ratio of attracting the opulence.
It too boost up the creative abilities to think each time creatively and catches the attention of people to gain name and fame. The resonating vibes furthermore motivates to learn new things, to eliminate out the hurdles and get the clean path for running to attain what desired.
It likewise infuses the leadership qualities along with the decision-making capability, the vivacity of the gem helps to welcome the openness of the ideas along with the good sense of humor.

Healing Properties

Aventurine includes a number of benefits that it provides to its wearer. They are:

Physical Healing : Green Aventurine is beneficial for the heart and the heart related diseases. It is excellent for those who are suffering from cardiac conditions, recovering from illness or surgery, or having circulatory problems. It kindles into the person the life-giving energy that stimulates throughout his body thereby assisting in physical regeneration. It prevents heart attack, arteriosclerosis and boost in efforts for lowering down cholesterol levels in the body.

Green Aventurine is also considered as a beneficial agent for migraine pains, genito-urinary and fertility problems; dyslexia, dyspraxia, eyesight, especially astigmatism and far-sightedness; and cerebral palsy. Furthermore, it also assists in curing the adrenals, thymus gland, lungs, and the nervous system.

If a person is going under homeopathic medication, Aventurine can prove to be really good for him. Aventurine also has an anti-inflammatory effect and helps in easing skin ailments, such as spots, acne, eczema, rosacea, and skin allergies.

Emotional Healing : Green Aventurine is considered great in comforting energy balances by guiding the wearer to the path of harmony. It makes the anxiety, anger and irritation to cool down and help in dissolving everyday stress that happens due to a hectic life. Aventurine is considered effective in enhancing sleep quieting the negative thoughts that occur in the mind. The vibrational energy of this stone keeps the person grounded.

Aventurine instils the thought in wearer’s mind that every bad phase passes away soon, and one must fight with such situations with hope and faith.

Spiritual Healing : The green-colored Aventurine is an outstanding healer and harmonizer, amalgamating the emotional, intellectual, physical and auric bodies to align them and bringing them into a natural rhythm.  It melts down the negativity and the negative thoughts by balancing the yin and yang energies of the body. It encourages one to embrace change, renewal, and growth.

Heals and Balances Chakra : Being a comforter and heart healer by nature, Aventurine is believed to activate the heart chakra. It acts as a protective shield for the heart chakra saving it from any sort of emotional turmoil.

The heart chakra is considered to set-up our connection with the outside world. It gives the wearer the ability to be himself in the environment. When the heart chakra is unbalanced, it gives the wearer the feeling that he is being controlled by somebody. The energy of this green crystal unclogs blockages and re-balances the Heart Chakra.

Blue and yellow Aventurine crystal is thought to open the third eye chakra. It is a strong mental healer that enhances the positive outlook in the wearer, develops the inner strength of the person, and assists in self-discipline. It is, moreover, used to balance the male/female energies in the one who wears it.

A red Aventurine crystal opens and supports the heart chakra, and helps the wearer to find out new opportunities for himself in life.

Where is Aventurine found?

Aventurine quartz crystals have largely been found in Brazil, India, Nepal, Italy, China, Tibet, and Russia.

Aventurine Facts

Some facts about Aventurine

  • Aventurine is the birthstone for the people having Virgo as their zodiac sign.
  • Aventurine utilises the wood energy and hence it is good for nourishment, expansion and growth of the house and its natives.
  • Green Aventurine is capable enough of absorbing the environmental pollution.
  • In ancient Tibet, people used to insert Aventurine stones in the status, especially in the place of eyes to increase the visionary value of the person.
  • It is termed as ‘fairy treasure”, and is believed that by keeping three green Aventurine stones in the garden, one can easily give way to good luck and fortune to appear in his house.
  • Aventurine is considered effective while conceiving a baby.

  • Metaphysical Properties

    Aventurine is the member of the family of Quartz categorized by vivid and bright insertions of Mica or other minerals that give this incredible a more incredible effect by adding glisten and shimmer to it. The iridescent or glistening effect displayed on Aventurine is known as aventurescence. This effect is more noteworthy when it is polished or tumbled.

    The name of Aventurine has been derived from the Italian “a venture” or “all ‘a Ventura”, which means “by chance.” It refers to one of the incidents that took place in the 1700’s, when in an industry; a worker accidently dropped metal filings into molten glass. The resultant effect of the material cools down was haphazardly spaced shimmering sparkles. It was used for the purpose of jewellery making and other stuff. Later, Aventurine was given the name of Aventurine because of its similarity to that industrial product.

    The hardness of Aventurine is about 7 on the Moh’s scale.

    Aventurine Color

    Aventurine is generally green in color, although it is also found in blue, red to auburn, carrots or peach, dusty purple, yellow, and silver-gray. It is mostly semi-transparent and often with stripes, but an excess of included minerals may provide it an opaque texture. The green color in Aventurine comes from Fuchsite particles in Quartz while the shades of brown, red, orange, are attributed to the inclusions of Goethite or Hematite minerals. The Aventurines, which are yellow and peach in color, include Pyrite with Mica; the purple variant contains Lepidolite while the blue variety of Aventurine contains inclusions of Dumortierite.

    Aventurine Colors

    https://www.jewelexi.com/gemstones/aventurine

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13 Fascinating Facts About Aquamarine

13 Fascinating Facts About Aquamarine

diamond

March Birthstone

Many people know that the aquamarine gemstone is the birthstone for March. It is also highly recognizable for its beautiful, clear blue color. What many people do not know is that this icy blue gem has been believed throughout the ages to possess mystical powers! Here are 13 fascinating facts about aquamarine.

Name and Uses

Aquamarine gets its name from Latin “aqua marina” which means “sea water.” It references the similarity of the gemstone’s color and clarity to that of the ocean.
Decorative jewelry and protective amulets using aquamarine have been found that date back as far as 500 B.C. It has been used for its great beauty and for its powers of healing, especially the ability to calm and sooth the nerves.

Protection for Sailors

Believed to be a precious treasure from mermaids, sailors have worn aquamarine amulets to keep them safe at sea, ward off seasickness, and protect them from Satan.

Healing Properties

This beautiful gem is believed, even now, to be a powerful meditation tool. It is supposed to lead the meditator to his or her core spirituality.The Romans believed that aquamarines could cure medical problems with the liver, stomach, and throat. Healers used it to reduce fluid retention and to calm the nerves.
In the Middle Ages, this gemstone was used to reduce anxiety and the toxicity of poisons.

Mystical Powers

Wearing aquamarine was believed to increase courage, happiness, intelligence, wisdom, and youthfulness. It was also used to protect against gossip!
Today aquamarine is considered a symbol of faithfulness, courage, and friendship.
Known as the birthstone for the month of March, this gem is also the wedding anniversary gemstone for the 19th year of marriage. It is associated with the zodiac sign of Pisces and the planet Neptune.

Aquamarine Properties

The aquamarine is a semi-precious gem is a member of the beryl family, which includes emerald and morganite. Aquamarine gemstones are graded using the same system as for diamonds – by color, cut, clarity, and carat weight.
Rated 7.8 on the Mohs hardness scale, aquamarine is soft enough to accommodate a wide variety of gemstone cutting styles and shapes. Lapidaries continue to experiment to fine new ways of enhancing this gem.

Favorite of Designers

Aquamarine is favorite gemstone among contemporary jewelry designers because even the palest blue gem can be a stunning jewel. It lends itself to such an assortment of shapes and cuts, that it gives designers great freedom in artistic expression.

Color

Aquamarine ranges in color from sea-foam green, to blue-green, to teal. The color is graded on its hue, tone, and saturation – hue for whether it is a warm or cool shade, tone for how light or dark the color is, and color saturation for the quality of being dull or a vivid blue.

Heat Treating

Although different shades of aquamarine have been popular at certain times in history, currently the preferred color is a lovely sky-blue. Some greenish colored aquamarines are heat treated to improve their clarity and change their color to a light blue. Heat treatment is almost impossible to detect. The changes caused by the treatment are permanent. The treatment usually adds value to the gem because of the color improvement.

Location

While the most valuable aquamarines are mined in Columbia and Brazil, caches of the gem have been found even in the Colorado Rocky Mountains. Other mines extracting gem quality material are found in Kenya, Zambia, Afghanistan, Pakistan, Sri Lanka, Russia, Tanzania, Nigeria, and Madagascar.

Raw Material

Although non-gem quality aquamarine crystal has been found at weights up to several tons, the largest gem quality raw stone was found in Brazil in 1910 in the village of Minas Gerais. This 243-pound raw aquamarine was cut into more than 100,000 carats of finished gemstones.

The Don Pedro

The world’s largest cut aquamarine, named the Don Pedro, is exhibited at the Natural History Museum at the Smithsonian in Washington, D.C.

Aquamarine Care

Aquamarine is very durable and does not require any special care. Unless the jewel has an internal occlusion (flaw), it is safe to use in ultrasonic cleaners. At-home care requires only a soft brush and soapy water. Rinse and wipe.

The beautiful range of colors, sizes, and ability to dazzle, as well as its mystical qualities, have made the aquamarine a favorite among gems for over two thousand years. Tell us which of our 19 facts and folklore items tickled your fancy!

http://www.turleyjewelers.com/blog/13-fascinating-facts-about-aquamarine

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Apatite

Apatite

Apatite
Last updated : October 24, 2017 7:47 AM

Apatite is a stone that is known for its power that helps in achieving goals, and clearing the feelings of anger, apathy and confusion. Apatite has received its name from a Greek word, which means to deceive. Apatite has received this name because of the diverse formations and variety of colours that it holds, which makes it easy to mistake it from other stones. Apatite is a stone that can magically encourage the ideas and thoughts. It is associated largely in conjunction with intellect, meditation, physic awareness, and imagination. Apatite is relatively a soft gemstone and is therefore used widely for jewellery purposes.

Physical Healing : A variety of Apatite, which is blue in colour promotes the manufacture and development of new cells and aids in the incorporation of calcium in the bones. It helps to nurse back healthy bones and teeth, looks after cartilage and is valuable in the treatments for joint problems, rickets, arthritis, and motor skills.

Apatite is also linked with healthy eating and has been attributed to holding back hunger and increasing metabolic rate. It is generally supportive in reducing hypertension, and healing glands and organs.

Emotional Healing : Apatite is believed to increase enthusiasm and building up energy reserves in the body when the body feels lethargic. It helps to triumph over shyness and introvert nature and helps the wearer to get rid of the feeling of alienation. Apatite is also recognised to promote honesty, social ease, and openness with others. It is useful in lessening grief and annoyance, and in reducing bad temper and emotional fatigue.

Spiritual Healing : Apatite is considered to develop the consciousness of past-life experiences and may also augment the understanding of karmic influences on the wearer’s current life and reality. According to a belief, the vibration of Apatite attracts towards it the “blue beings” of the heavenly nature whether divine entities such as Krishna, ETs or extraterrestrials, and allows one to communicate with them.

Heals and Balances Chakra : Apatite is associated with the Third Eye and the Throat Chakras. It is an excellent stone for balancing the yin and yang of the body. The Third Eye or the brow chakra is the centre of our insight and command. It lets the wearer be in harmony with the worldly awareness and knowledge.

By balancing the throat chakra, it balances the overall voice of the body. It helps the wearer in communicating his opinions, thoughts, and feelings to others.

Where is Apatite found?

Apatite is a very common stone, and the noteworthy places where it is found are Germany, Portugal, Russia, Afghanistan, Pakistan, and Morocco. However, the major sources of Apatite are Mexico, Brazil, and Burma.

Other sources include Canada, Czech Republic, India, Spain, Sri Lanka, Madagascar, Mozambique, South Africa, Norway, and the United States.

Apatite Facts

Some facts about Apatite

  • It is believed that Apatite can build a connection with the UFO’s.
  • In earlier times, Apatite was used as fertilizers.
  • Apatite is not much known about its relation to any myth or folklore.
  • Blue Apatite honours the Greek Earth Mother Goddess called Gaia.

Metaphysical Properties

The Apatite mineral members were traditionally known as Chlorapatite, Fluorapatite, and Hydroxyl-Apatite. Apatite is one of those minerals, which are formed and used by natural micro-environmental systems.

Apatite is the main resource of the phosphorus that is essential for plants. The teeth and bones of most of the animals, including humans, are comprised of calcium phosphate, which is the similar substance as Apatite.

On Moh’s scale of hardness, Apatite weighs 5.

Apatite Color

Apatite is the standard term for many phosphates and a mineral group as well, but superior-quality apatite is a special stone that is found in a beautiful variety of colours. The colours in which the Apatite is formed in are white, yellow, brown, gray, red, pink, purple, blue, green, and sometimes multicoloured.

Apatite Colors

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Andesine Feldspar

Feldspar Gemstones

From the perspective of the gemstone world, it would seem like quartz is the most abundant mineral in the world. The many quartz varieties include citrine, amethyst, ametrine, chalcedony, aventurine, onyx, agate, tiger’s eye, smoky quartz and rose quartz.

But from the viewpoint of mineralogy, it is feldspar that is the most common mineral. In fact feldspar makes up nearly 60% of the Earth’s crust. Feldspar is a group of minerals distinguished by the presence of aluminum silicates with potassium, sodium, calcium and barium.

The name feldspar comes from the fact that some early specimens were found in fields. The term spar is a generic term used by geologists to refer to any non-metallic mineral with a vitreous luster that breaks on distinct planes. The mineral was officially given its name by Johan Gottschalk Wallerius in 1747.

There are two main subgroups of feldspar that produce gem-quality material; the potassium feldspars and the plagioclases, a series that range from calcium to sodium feldspars. Among the well-known feldspar gemstones are moonstone, orthoclase, amazonite, andesine, labradorite and sunstone.

Amazonite, moonstone and orthoclase are all potassium feldspars. They have a hardness of 6 to 6.5 on the Mohs scale and a vitreous luster. Moonstone also exhibits a unique shimmer known as adularescence.

Labradorite, andesine and sunstone are plagioclases feldspars. Like the potassium feldspars, they have a hardness of 6 to 6.5, but they differ in their tendency to have slightly higher refractive indices, ranking between beryl and quartz.

Apart from gemstones, feldspar is an important industrial mineral. It is a common raw material in the production of ceramics and geopolymers, and is also often used as an anti-caking agent in powdered forms of non-dairy creamer. Additionally, feldspar is an important ingredient in the manufacturing of glass. The alkali content in feldspar acts as a flux, lowering the glass batch melting temperature and reducing production costs.

Granite, an important building material, contains 50% to 70% alkaline feldspar. Feldspars are generally light-colors, such as white, pink, tan, green or gray. The color varies due to impurities within the crystal structure. Feldspar is the mineral that gives granite its pink, green or gray color.

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Andalusite – The Unknown Star

Andalusite – The Unknown Star Article Comments

Andalusite is a beautiful semi-precious gemstone with a diverse and changeable personality. It is often used in art objects and jewelry. Andalusite was first discovered in Andalucia, Southern Spain from which it gets its name.

There are some good reasons for its artistic popularity. Andalusite is known for its pleochroism. Pleochroic minerals reflect different colors resulting from the absorption of different wavelengths of light traveling through the crystal from different directions. Mother Nature produces andalusite in brown, green, red, yellow, greenish-brown and brownish-green. Other gemstones that share pleochroic characteristic include carletonite, elbaite, iolite, kunzite, tanzanite and zoisite.

Asterism is another light effect that occurs in some gemstones. Some andalusites benefit from this phenomenon. The Greek word aster means star. When some crystal gemstones are formed, minute needle-like mineral deposits form a star or cross shape in the gemstone. This variety of andalusite is called chiastolite and contains the dark mineral strips of carbon or clay, which form an X or cross. These andalusite gemstones are sometimes used in the creation of inspirational items and jewelry. Check out tigereyejewels.com to see a magnificent multi-gemstone Rosary featuring andalusite. Star Sapphires, star rubies and star rose quartz are all the result of asterism.

Another gemstone effect that is similar to asterism is called cat’s eyes. It is caused by the same inclusion of minute mineral crystals imbedded in gemstones and reflecting light. However, with the cat’s eye affect the imbedded mineral shimmers from top to bottom. Andalusite is one of the most common cat’s eye stones. The cat’s eye effect is also known as the chatayancy, which comes from the French word for cat (chat – pronounced, shot).

Relating cats to gemstones is an ancient trend that we still enjoy today. Tiger eye gemstone has been popular since ancient times and just as andalusite has its particular beauty expressed in terms of cats. You can see the two gemstones elegantly combined at tigereyejewels.com.

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About Ammolite – History and Introduction

About Ammolite – History and Introduction

Ammolite, often referred to as ammonite, is arguably one of the rarest gemstones on earth. Ammolite belongs to a small group of organic gemstones, which also includes amber, coral, jet and pearl. Ammolite is composed of the fossilized shell remains of ammonites, primarily aragonite, the same material that makes up nacreous pearls. Ammolite’s highly desirable, opal-like, iridescent play-of-color typically occurs in shades of green and red, but all of the spectral colors are possible. Top grade ammolite stones should not show any visible matrix. Ammolite sources and deposits are expected to be depleted and exhausted within the next twenty years. Ammolite often has a flaky or “dragon skin” surface. To an extent, this is normal, but excessive scaling will reduce ammolite’s value.

Ammolite is also known as ‘aapoak’, which originated from an Indian Kainah word, meaning “small, crawling stone”. Other trade names include gem-ammonite, korite and calcentine. Korite International mining company is the world’s leading commercial provider for gem quality ammolite. The term ‘ammonite’ was originally used to describe the spiral shape of the fossilized shells, which closely resembled the shape of ram’s horns.

Ammolite Gemstone

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There are a few gemstones that can mimic ammolite, including labradorite, spectrolite and opal, all of which can have a similar appearance. However, ammolite can usually be distinguished quite easily through close inspection. Ammolite’s iridescence is a result of aragonite’s unique microstructure, making it different than most other gemstones with iridescence. Typically, iridescence is a result of light absorption, but ammolite color is a result of light interference rebounding off thin layers of platelets, which are part of aragonite’s organic structure. Labradorite most often occurs in blue and purple colors, whereas ammolite is typically found in red and green. Both labradorite and opal play-of-color appear to “roll-across” the stone, unlike the restricted play-of-color seen with ammolite. The visible structures of ammolite are also very unique, distinguishing it from look-a-likes. Imitations will usually appear transparent to translucent depending on the perspectives viewed, but natural ammolite is opaque.

Sources of ammonite do exist in various locations around the world, but Ammolite is sourced primarily (over 90%) from one location along the eastern slopes of the Canadian Rockies in Alberta, Canada. In 1981, mining for ammolite escalated to a commercial level and during this time, the World Jewellery Confederation (CIBJO) declared ammolite an official variety of colored gemstone.

In 2004, Alberta declared ammolite as its provincial gemstone and in 2007, the City of Lethbridge also declared ammolite to be its official gemstone. The best deposits are along high energy river systems on the eastern slopes of the Canadian Rockies. Most of the commercial mining is conducted along the St. Mary River and approximately 50% of all ammolite is mined from within the Indian Kainah reserve. Since 2003, an eco-friendly mining company, Korite International, has been the world’s leading provider for gem quality ammolite. Utah based, Seafire Gems is also known to produce specimens of gem quality ammolite. If the current production rate of fine ammolite continues, ammolite mines are expected to be worked out within 20 years.

Ammolite Color

Ammolite color is owed to an optical phenomenon known as iridescence. Iridescence allows ammolite to display an incredible play-of-color similar to precious opal. Ammolite color depends on the angle of light and the viewing angle. Iridescence can range from subtle to dramatic color shifts. Ammolite is known to have chromatic color shifts, such as red to green, or green to blue (dichromatic). Some ammolite color shifts are restricted to the same primary color group (monochromatic). The most valuable ammolite shifts through the entire color spectrum (spectrochromatic).

Rotational range, separate from play-of-color, also affects ammolite value. The best ammolite will display vivid colors from a full 360-degree rotational range. Others may exhibit colors only from a limited rotational range. Specimens with color ranges of 241-360° and 180°-240° are considered to be more desirable. Those with 90°-179° degree color limitations are not as valuable, but since all ammolite is rare, any gem quality specimen is in high demand. Crimson, violet and gold ammolite are the rarest color combinations.

Ammolite Clarity and Luster

Ammolite is naturally opaque. Almost all ammolite specimens will include part of the host matrix (typically clay, limestone or shale). Ammolite has a near vitreous luster and can appear slightly resinous when stabilized with epoxy, polymer or resins.

Ammolite Cut and Shape

Ammolite is almost always cut into free-form slabs. Calibrated stones (and round or fancy shapes) will command a very high premium. Most ammolite is fabricated into doublet or triplet stones. Ammolite triplets are ideal for use in cabochon rings. Ammolite is very rarely offered in an untreated state.

Ammolite Treatment

Ammolite is typically enhanced by layering. Without enhancements, ammolite is far too fragile for use in jewelry. Layering is common in the gem trade and it is most often seen in the form of opal doublets or triplets. Ammolite is often stabilized through impregnation of lacquer, polymer, epoxy or resins. Ammolite doublets consist of a hard bottom, typically obsidian or another type of glass, and a thin strip of ammolite glued on top. Triplets include a third clear crystal layer to enhance durability and iridescence, such as synthetic spinel. Layering of assembled doublets and triplets is very common and accepted in the gem trade as long as treatment is disclosed. Layering treatments enhance durability and in most cases, can also enhance color.

Chemical Formula: Calcium carbonate (CaCO3); 3-4% variable mineral traces).
Crystal Structure: Orthorhombic
Color: Gray-brown, multicolored iridescence
Hardness: 4 on the Mohs scale (varies in composition.)
Refractive Index: 1.52 – 1.68
Density: 2.75 – 2.80
Cleavage: Pinacoidal
Transparency: Opaque
Double Refraction / Birefringence: 0.155
Luster: Greasy to dull; vitreous to resinous
Fluorescence: Ultraviolet light – mustard yellowish

Ammolite is an extremely difficult gemstone to imitate. However, there are a few gemstones that bear similar resemblance, some of which, include labradorite, spectroliteand precious opal. Though ammolite is rarer than opal, black opal is more valuable, which sometimes results in ammolite being used as an alternative or imitatation black opal. Since ammolite belongs to the organic group of gemstones, some varieties of organic gems, as well as shell-based marbles can often be confused with ammolite. Since ammolite is composed mostly of the fossilized shell remains of ammonites, which also make up the composition of nacreous pearls, both pearl and mother-of-pearl are very closely related to ammolite fossils. As a fossil gemstone, its process of formation is similar to that of fossil coral, amber, petrified wood and jet. The iridescent colors and optical phenomena of ammolite is very unique, but it is not the only gemstone to exhibit stunning color effects. Other gemstones which exhibit beautiful and rare colorful effects, include hackmanite, rainbow pyrite, fire agate, varieties of opal and moonstone.

Most Popular Similar or Related Gemstone Varieties and Trade Names:

Labradorite, precious opal, black opal, fire opal, chocolate opal, pearl, mother of pearl, coral, fossil coral, amber and jet are the most common similar or related gemstone varieties and trade names.

Lesser Known Similar or Related Gemstone Varieties and Trade Names:

Hackmanite, opal in matrix, fire marble, fossilized clam, snail shell, spectrolite, petrified wood, peanut wood and abalone shell are lesser-known similar or related gemstone varieties and trade names.

Ammolite powers and metaphysical beliefs can be traced back through many centuries. Although ammolite is relatively new commercially, native tribes have been using ammolite for hundreds of years. The Blackfeet Indians named ammolite the ‘Buffalo Stone’, because they would find ammolite fragments washed-up on river banks, often with silhouettes reminiscent of buffaloes. Buffaloes represented wealth, health, power and stamina. Blackfeet tribesman believed ammolite possessed strong healing powers and often mixed the gem into medicines.

After ammolite was introduced to the rest of the world in the 1990s, ammolite became very popular among practitioners of feng shui. It was known as an “influential” stone. It was believed that ammolite had the power to enhance and detoxify the body with “chi”. It was later given the name of “Seven Color Prosperity Stone”. Each ammolite color influenced its wearer with a different “chi” or energy. Ancient Egyptians named the fossil after one of their gods, Ammon, because ammolite resembled the shape of ram’s horns. Ammonite was highly prized by Egyptians, Romans and Ethiopians alike. Ammolite was worn in the belief that prophetic dreams would come to them, and it would help with deep meditation.

Other ammolite powers include the ability to change negativity into flowing energy. It is thought to ease childbirth, reduce depression and relieve harmful thoughts and patterns. Since ammolites are fossils of once living creatures, they are linked to the fifth element, Akasha. Ammolite is also the stone of Aquarius and is assigned to the first (root/base) chakra.

Disclaimer: Metaphysical and Alternative Crystal Healing Powers and Properties are not to be taken as confirmed advice. Should you have any medical conditions, please see a licensed practitioner. This information is not to replace the advice of your doctor. GemSelect does not guarantee any claims or statements made and cannot be held liable under any circumstances.

Ammolite deposits are quite rare and only 50% of all finds are suitable for jewelry. Ammolite stones have been used as amulets for a very long time. Ammolite is usually fashioned into freeform shapes and mounted in silver or gold. The colors are best highlighted with transparent crystal accents such as spinel. Even though ammolite is typically layered as doublets or triplets, it is still fragile. Therefore, ammolite is best suited for use in pendants, earrings or brooches.

Ammolite gemstones can be worn as rings, but only when they are layered into triplets. Spinel is most popular for creating ammolite triplet gemstone rings. Because Canada is the number one source for creating and trading ammolite jewelry, artisans often sell ammolite jewelry to tourists visiting Banff National Park. In the United States, ammolite is very popular among the Zuni tribe and other Native American craftsmen.

Note: Buy colored gemstones by size and not by carat weight. Colored stones vary in size-to-weight ratio. Some stones are larger and others are smaller than diamonds by weight in comparison.

How to Clean your GemstonesLike all organic gemstones, caring for ammolite requires extra attention. Ammolite can be cleaned with warm water and a soft cloth. Mild soap or detergent can be used if needed, but avoid harsh chemicals, including bleach, perfume or hairspray. Excessive heat and acid can weaken stability and iridescence. Though triplets are slightly more durable, the same level of care should be taken for all ammolite. Avoid hard blows, because it can cause damage and separation of doublet or triplet layers. Ammolite should be stored separately from other stones because it can be easily scratched by other gems. A silk bag, soft cloth or velvet-lined box is ideal for use when storing ammolite.

 

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