Dachshunds – Part 4

Temperament (Continued)

Dachshunds can be aggressive to strangers and other dogs. Despite this, they are rated in the intelligence of dogs as an average working dog with a persistent ability to follow trained commands 50% of the time or more. They rank 49th in Stanley Coren’s Intelligence of Dogs, being of average working and obedience intelligence. They can have a loud bark. Some bark quite a lot and may need training to stop, while others will not bark much at all. Dachshunds are known for their devotion and loyalty to their owners, though they can be standoffish towards strangers. If left alone too frequently, some dachshunds are prone to separation anxiety and may chew objects in the house to relieve stress.

Dachshunds are burrowers by nature and are likely to burrow in blankets and other items around the house, when bored or tired.

Mini dachshund displaying typical burrowing behavior

Dachshunds can be difficult to housebreak, and patience and consistency are often needed in this endeavor.

Dachshund puppy

According to the American Kennel Club’s breed standards, “the dachshund is clever, lively and courageous to the point of rashness, persevering in above and below ground work, with all the senses well-developed. Any display of shyness is a serious fault.” Their temperament and body language give the impression that they do not know or care about their relatively small size. Like many small hunting dogs, they will challenge a larger dog. Indulged dachshunds may become snappy or extremely obstinate.

Many dachshunds do not like unfamiliar people, and many will growl or bark at them. Although the dachshund is generally an energetic dog, some are sedate. This dog’s behavior is such that it is not the dog for everyone. A bored, untrained dachshund will become destructive. If raised improperly and not socialized at a young age, dachshunds can become aggressive or fearful. They require a caring, loving owner who understands their need for entertainment and exercise.

Dachshunds may not be the best pets for small children. Like any dog, dachshunds need a proper introduction at a young age. Well-trained dachshunds and well-behaved children usually get along fine. Otherwise, they may be aggressive and bite an unfamiliar child, especially one that moves quickly around them or teases them. However, many dachshunds are very tolerant and loyal to children within their family, but these children should be mindful of the vulnerability of the breed’s back.

A 2008 University of Pennsylvania study of 6,000 dog owners who were interviewed indicated that dogs of smaller breeds were more likely to be “genetically predisposed towards aggressive behavior”. Dachshunds were rated the most aggressive, with 20% having bitten strangers, as well as high rates of attacks on other dogs and their owners. The study noted that attacks by small dogs were unlikely to cause serious injuries and because of this were probably under-reported.

Health

Two dachshund puppies

The breed is prone to spinal problems, especially intervertebral disk disease (IVDD), due in part to an extremely long spinal column and short rib cage. The risk of injury may be worsened by obesity, jumping, rough handling, or intense exercise, which place greater strain on the vertebrae. About 20–25% of dachshunds will develop IVDD.

Treatment consists of combinations of crate confinement and courses of anti-inflammatory medications (steroids and non-steroidal anti-inflammatory drugs like carprofen and meloxicam), or chronic pain medications, like tramadol. Serious cases may require surgery to remove the troublesome disk contents. A dog may need the aid of a cart to get around if paralysis occurs.

A minimally invasive procedure called “percutaneous laser disk ablation” has been developed at the Oklahoma State University Veterinary Hospital. Originally, the procedure was used in clinical trials only on dachshunds that had suffered previous back incidents. Since dachshunds are prone to back issues, the goal is to expand this treatment to dogs in a normal population.

In addition to back problems, the breed is prone to patellar luxation where the kneecap can become dislodged. Dachshunds may also be affected by Osteogenesis imperfecta (brittle bone disease). The condition seems to be mainly limited to wire-haired Dachshunds, with 17% being carriers. A genetic test is available to allow breeders to avoid breeding carriers to carriers. In such pairings, each puppy will have a 25% chance of being affected.

In some double dapples, there are varying degrees of vision and hearing loss, including reduced or absent eyes. Not all double dapples have problems with their eyes and/or ears, which may include degrees of hearing loss, full deafness, malformed ears, congenital eye defects, reduced or absent eyes, partial or full blindness, or varying degrees of both vision and hearing problems; but heightened problems can occur due to the genetic process in which two dapple genes cross, particularly in certain breeding lines. Dapple genes, which are dominant genes, are considered “dilution” genes, meaning whatever color the dog would have originally carried is lightened, or diluted, randomly; two dominant “dilution” genes can cancel each other out, or “cross”, removing all color and producing a white recessive gene, essentially a white mutation. When occurring genetically within the eyes or ears, this white mutation can be detrimental to development, causing hearing or vision problems.

Other dachshund health problems include hereditary epilepsy, granulomatous meningoencephalitis, dental issues, Cushing’s syndrome, thyroid and autoimmune problems, various allergies and atopies, and various eye conditions including cataracts, glaucoma, progressive retinal atrophy, corneal ulcers, nonucerative corneal disease, sudden acquired retinal degeneration, and cherry eye. Dachshunds are also 2.5 times more likely than other breeds of dogs to develop patent ductus arteriosus, a congenital heart defect. Dilute color dogs (Blue, Isabella, and Cream) are very susceptible to Color Dilution Alopecia, a skin disorder that can result in hair loss and extreme sensitivity to sun. Since the occurrence and severity of these health problems is largely hereditary, breeders are working to eliminate these.

Factors influencing the litter size of puppies and the proportion of stillborn puppies per litter were analyzed in normally sized German dachshunds. The records analyzed contained data on 42,855 litters. It was found that as the inbreeding coefficient increased, litter size decreased and the percentage of stillborn puppies increased, thus indicating inbreeding depression. It was also found that young and older dams had smaller litter sizes and more stillborn puppies than middle-aged dams.

More about Dachshunds in Part 5! Stay tuned!

(Information from Wikipedia, the free encyclopedia)

Dachshunds – Part 3

Size

Dachshunds come in three sizes: standard, miniature, and kaninchen (German for “rabbit”). Although the standard and miniature sizes are recognized almost universally, the rabbit size is not recognized by clubs in the United States and the United Kingdom. The rabbit size is recognized by the Fédération Cynologique Internationale (World Canine Federation) (FCI), which contain kennel clubs from 83 countries all over the world. An increasingly common size for family pets falls between the miniature and the standard size, frequently referred to as “tweenies,” not an official classification.

A full-grown standard dachshund averages 16 lb (7.3 kg) to 32 lb (15 kg), while the miniature variety normally weighs less than 12 lb (5.4 kg). The kaninchen weighs 8 lb (3.6 kg) to 11 lb (5.0 kg). According to kennel club standards, the miniature (and kaninchen, where recognized) differs from the full-size only by size and weight, thus offspring from miniature parents must never weigh more than the miniature standard to be considered a miniature as well. While many kennel club size divisions use weight for classification, such as the American Kennel Club, other kennel club standards determine the difference between the miniature and standard by chest circumference; some kennel clubs, such as in Germany, even measure chest circumference in addition to height and weight.

H. L. Mencken said that “A dachshund is a half-dog high and a dog-and-a-half long,” although they have been referred to as “two dogs long” This characteristic has led them to be quite a recognizable breed, and they are featured in many jokes and cartoons, particularly The Far Side by Gary Larson.

Eye color

Red piebald long hair miniature dachshund puppy

Light-colored dachshunds can sport amber, light brown, or green eyes; however, kennel club standards state that the darker the eye color, the better. Dapple and double dapple dachshunds can have multi coloured “wall” eyes with fully blue, partially blue or patched irises due to the effect of the dapple gene on eye pigmentation expression. “Wall” eye is permissible according to DCA standards but undesirable by AKC standards. Piebald-patterned dachshunds will never have blue in their eyes, unless the dapple pattern is present.

Popularity

Dachshunds are one of the most popular dogs in the United States, ranking 13th in the 2016 AKC registration statistics. They are popular with urban and apartment dwellers, ranking among the top ten most popular breeds in 76 of 190 major US cities surveyed by the AKC. One will find varying degrees of organized local dachshund clubs in most major American cities, including New York, New Orleans, Portland, Los Angeles, and Chicago.

Temperament

Dachshunds are playful, but as hunting dogs can be quite stubborn, and are known for their propensity for chasing small animals, birds, and tennis balls with great determination and ferocity. Many dachshunds are stubborn, making them a challenge to train.

Being the owner of dachshunds, to me a book on dog discipline becomes a volume of inspired humor. Every sentence is a riot. Some day, if I ever get a chance, I shall write a book, or warning, on the character and temperament of the dachshund and why he can’t be trained and shouldn’t be. I would rather train a striped zebra to balance an Indian club than induce a dachshund to heed my slightest command. When I address Fred I never have to raise either my voice or my hopes. He even disobeys me when I instruct him in something he wants to do.— E. B. White

More about these lovable dogs, nicknamed “wiener dogs” in Part 4.

(Information From Wikipedia, the free encyclopedia)

Dachshund – Part 2

Characteristics

Appearance

A wire-haired dachshund

A typical dachshund is long-bodied and muscular with short stubby legs. Its front paws are disproportionately large, being paddle-shaped and particularly suitable for digging. Its skin is loose enough not to tear while tunneling in tight burrows to chase prey. The dachshund has a deep chest which provides appropriate lung capacity for stamina when hunting. Its snout is long. According to the AKC standards for the breed, “scars from honorable wounds shall not be considered a fault” because the dachshund is a hunting dog.

Coat and color

A redhaired miniature dachshund

There are three dachshund coat varieties: smooth coat (short hair), long haired, and wire haired. Long haired dachshunds have a silky coat and short feathering on legs and ears. Wire haired dachshunds are the least common coat variety in the United States (although it is the most common in Germany) and the most recent coat to appear in breeding standards. Dachshunds have a wide variety of colors and patterns, the most common one being red. Their base coloration can be single-colored (either red or cream), tan pointed (black and tan, chocolate and tan, blue and tan, or isabella and tan), and in wire haired dogs, a color referred to as wild boar. Patterns such as dapple (merle), sable, brindle and piebald also can occur on any of the base colors. Dachshunds in the same litter may be born in different coat colors depending on the genetic makeup of the parents. The dominant color in the breed is red, followed by black and tan. Tan pointed dogs have tan (or cream) markings over the eyes, ears, paws, and tail. The reds range from coppers to deep rusts, with or without somewhat common black hairs peppered along the back, face and ear edges, lending much character and an almost burnished appearance; this is referred to among breeders and enthusiasts as an “overlay” or “sabling”. Sabling should not be confused with a more unusual coat color referred to as sable. At a distance, a sable dachshund looks somewhat like a black and tan dog. Upon closer examination, however, one can observe that along the top of the dog’s body, each hair is actually banded with red at the base near the skin transitioning to mostly black along the length of the strand. An additional striking coat marking is the brindle pattern. “Brindle” refers to dark stripes over a solid background—usually red. If a dachshund is brindled on a dark coat and has tan points, it will have brindling on the tan points only. Even one single, lone stripe of brindle is a brindle. If a dachshund has one single spot of dapple, it is a dapple.

The Dachshund Club of America (DCA) and the American Kennel Club (AKC) consider both the piebald pattern and the double dapple (double merle) pattern to be nonstandard. However, both types continue to be shown and sometimes even win in the conformation ring.

Dogs that are double-dappled have the merle pattern of a dapple, but with distinct white patches that occur when the dapple gene expresses itself twice in the same area of the coat. The DCA excluded the wording “double-dapple” from the standard in 2007 and now strictly uses the wording “dapple” as the double dapple gene is commonly responsible for blindness and deafness.

There are three types of dachshund, which can be classified by their coats: short-haired, called ‘smooth’; long-haired; and wire-haired.

Long Haired Dachshund

More about these cute little dogs in Part 3.

(Information from Wikipedia, the free encyclopedia )

Dachshund – Part 1

The dachshund, also known as the sausage dog or wiener dog is a short-legged, long-bodied, hound-type dog breed. They may be smooth-haired, wire-haired, or long-haired.

The standard-size dachshund was developed to scent, chase, and flush out badgers and other burrow-dwelling animals, while the miniature dachshund was bred to hunt smaller prey such as rabbits. In the Western United States, they have also been used to track wounded deer and hunt prairie dogs.

Dachshunds also participate in conformation shows, field trials and many other events organized through pure-bred dog organizations such as the American Kennel Club (AKC). According to the AKC, the dachshund is ranked in 13th place in popularity among dog breeds in the United States.

The name dachshund is of German origin and literally means “badger dog,” from Dachs (“European badger”) and Hund (“hound, dog”). The pronunciation varies widely in English: variations of the first and second syllables include /ˈdɑːks-/, /ˈdæks-/ and /-hʊnt/, /-hʊnd/, /-ənd/. Although “dachshund” is a German word, in modern German they are more commonly known by the short name Dackel or Teckel. The German word is pronounced [ˈdaks.hʊnt].

Because of their long, narrow build, they are often nicknamed wiener dog or sausage dog. Dachshund may be mispronounced as “dash-hound” by some English speakers.

Classification

While classified in the hound group or scent hound group in the United States and Great Britain, the breed has its own group in the countries which belong to the Fédération Cynologique Internationale (World Canine Federation). Many dachshunds, especially the wire-haired subtype, may exhibit behavior and appearance that are similar to that of the terrier group of dogs. An argument can be made for the scent (or hound) group classification because the breed was developed to use scent to trail and hunt animals, and probably descended from the Saint Hubert Hound like many modern scent hound breeds such as bloodhounds and Basset Hounds; but with the persistent personality and love for digging that probably developed from the terrier, it can also be argued that they could belong in the terrier, or “earth dog”, group.

More about these popular and cute little dogs, nicknamed “wiener dogs” in Part 2.

(Information from Wikipedia, the free encyclopedia)

Pearls – The Birthstone of June – Part 9

In Jewelry

The value of the pearls in jewelry is determined by a combination of the luster, color, size, lack of surface flaw and symmetry that are appropriate for the type of pearl under consideration. Among those attributes, luster is the most important differentiator of pearl quality according to jewelers.

All factors being equal, however, the larger the pearl the more valuable it is. Large, perfectly round pearls are rare and highly valued. Teardrop-shaped pearls are often used in pendants.

Shapes

Pearls come in eight basic shapes: round, semi-round, button, drop, pear, oval, baroque, circled and double bouldered. Perfectly round pearls are the rarest and most valuable shape. Semi-rounds are also used in necklaces or in pieces where the shape of the pearl can be disguised to look like it is a perfectly round pearl. Button pearls are like a slightly flattened round pearl and can also make a necklace, but are more often used in single pendants or earrings where the back half of the pearl is covered, making it look like a larger, rounder pearl.

Drop and pear shaped pearls are sometimes referred to as teardrop pearls and are most often seen in earrings, pendants, or as a center pearl in a necklace. Baroque pearls have a different appeal; they are often highly irregular with unique and interesting shapes. They are also commonly seen in necklaces. Circled pearls are characterized by concentric ridges, or rings, around the body of the pearl.

In general, cultured pearls are less valuable than natural pearls, whereas imitation pearls have almost no value. One way that jewelers can determine whether a pearl is cultured or natural is to have a gemlab perform an X-ray examination of the pearl. If X-rays reveals a nucleus, the pearl is likely a bead-nucleated saltwater pearl. If no nucleus is present, but irregular and small dark inner spots indicating a cavity are visible, combined with concentric rings of organic substance, the pearl is likely a cultured freshwater. Cultured freshwater pearls can often be confused for natural pearls which present as homogeneous pictures which continuously darken toward the surface of the pearl. Natural pearls will often show larger cavities where organic matter has dried out and decomposed.

Lengths of Pearl Necklaces

There is a special vocabulary used to describe the length of pearl necklaces. While most other necklaces are simply referred to by their physical measurement, pearl necklaces are named by how low they hang when worn around the neck. A collar, measuring 10 to 13 inches or 25 to 33 cm in length, sits directly against the throat and does not hang down the neck at all; collars are often made up of multiple strands of pearls. Pearl chokers, measuring 14 to 16 inches or 35 to 41 cm in length, nestle just at the base of the neck. A strand called a princess length, measuring 17 to 19 inches or 43 to 48 cm in length, comes down to or just below the collarbone. A matinee length, measuring 20 to 24 inches or 50 to 60 cm in length, falls just above the breasts. An opera length, measuring 28 to 35 inches or 70 to 90 cm in length, will be long enough to reach the breastbone or sternum of the wearer; and longer still, a pearl rope, measuring more than 45 inches or 115 cm in length, is any length that falls down farther than an opera.

Necklaces can also be classified as uniform, or graduated. In a uniform strand of pearls, all pearls are classified as the same size, but actually fall in a range. A uniform strand of akoya pearls, for example, will measure within 0.5 mm. So a strand will never be 7 mm, but will be 6.5–7 mm. Freshwater pearls, Tahitian pearls, and South Sea pearls all measure to a full millimeter when considered uniform.

A graduated strand of pearls most often has at least 3 mm of differentiation from the ends to the center of the necklace. Popularized in the United States during the 1950s by the GIs bringing strands of cultured akoya pearls home from Japan, a 3.5 momme, 3 mm to 7 mm graduated strand was much more affordable than a uniform strand because most of the pearls were small.

Colors

Earrings and necklaces can also be classified on the grade of the color of the pearl: saltwater and freshwater pearls come in many different colors. While white, and more recently black, saltwater pearls are by far the most popular, other color tints can be found on pearls from the oceans. Pink, blue, champagne, green, and even purple saltwater pearls can be encountered, but to collect enough of these rare colors to form a complete string of the same size and same shade can take years.

Whatever color or style chosen, wouldn’t you agree that Pearls are classic? Pearls can dress up an outfit but are also compatible with casual outfits.

(Information from Wikipedia, the free encyclopedia)

Pearls – The Birthstone of June – Part 8

Timeline of Pearl Production

Mitsubishi commenced pearl culture with the South Sea pearl oyster in 1916, as soon as the technology patent was commercialized. By 1931 this project was showing signs of success, but was upset by the death of Tatsuhei Mise. Although the project was recommenced after Tatsuhei’s death, the project was discontinued at the beginning of WWII before significant productions of pearls were achieved.

After WWII, new south sea pearl projects were commenced in the early 1950s at Kuri Bay and Port Essington in Australia, and Burma. Japanese companies were involved in all projects using technicians from the original Mitsubishi South Sea pre-war projects. Kuri Bay is now the location of one of the largest and most well-known pearl farms owned by Paspaley, the biggest producer of South Sea pearls in the world.

In 2010, China overtook Japan in akoya pearl production. Japan has all but ceased its production of akoya pearls smaller than 8 mm. Japan maintains its status as a pearl processing center, however, and imports the majority of Chinese akoya pearl production. These pearls are then processed (often simply matched and sorted), relabeled as product of Japan, and exported.

In the past two decades, cultured pearls have been produced using larger oysters in the south Pacific and Indian Ocean. The largest pearl oyster is the Pinctada maxima, which is roughly the size of a dinner plate. South Sea pearls are characterized by their large size and warm luster. Sizes up to 14 mm in diameter are not uncommon. In 2013, Indonesia Pearl supplied 43 percent of South Sea Pearls international market. The other significant producers are Australia, Philippines, Myanmar and Malaysia.

Freshwater Pearl Farming

In 1914, pearl farmers began growing cultured freshwater pearls using the pearl mussels native to Lake Biwa. This lake, the largest and most ancient in Japan, lies near the city of Kyoto. The extensive and successful use of the Biwa Pearl Mussel is reflected in the name Biwa pearls, a phrase which was at one time nearly synonymous with freshwater pearls in general. Since the time of peak production in 1971, when Biwa pearl farmers produced six tons of cultured pearls, pollution has caused the virtual extinction of the industry. Japanese pearl farmers recently cultured a hybrid pearl mussel – a cross between Biwa Pearl Mussels and a closely related species from China, Hyriopsis cumingi, in Lake Kasumigaura. This industry has also nearly ceased production, due to pollution. Currently, the Belpearl company based out of Kobe, Japan continues to purchase the remaining Kasumiga-ura pearls.

Japanese pearl producers also invested in producing cultured pearls with freshwater mussels in the region of Shanghai, China. China has since become the world’s largest producer of freshwater pearls, producing more than 1,500 metric tons per year (in addition to metric measurements, Japanese units of measurement such as the kan and momme are sometimes encountered in the pearl industry).

Led by pearl pioneer John Latendresse and his wife Chessy, the United States began farming cultured freshwater pearls in the mid-1960s. National Geographic magazine introduced the American cultured pearl as a commercial product in their August 1985 issue. The Tennessee pearl farm has emerged as a tourist destination in recent years, but commercial production of freshwater pearls has ceased.

Momme Weight

For many cultured pearl dealers and wholesalers, the preferred weight measure used for loose pearls and pearl strands is the momme. Momme is a weight measure used by the Japanese for centuries. Today, momme weight is still the standard unit of measure used by most pearl dealers to communicate with pearl producers and wholesalers. One momme corresponds to 1/1000 kan. Reluctant to give up tradition, the Japanese government formalized the kan measure in 1891 as being exactly 3.75 kilograms or 8.28 pounds. Hence, 1 momme = 3.75 grams or 3750 milligrams.

In the United States, during the 19th and 20th centuries, through trade with Japan in silk cloth the momme became a unit indicating the quality of silk cloth.

Though millimeter size range is typically the first factor in determining a cultured pearl necklace’s value, the momme weight of pearl necklace will allow the buyer to quickly determine if the necklace is properly proportioned. This is especially true when comparing the larger south sea and Tahitian pearl necklaces.

More information about Pearls in Part 9 of this series!

(Information from Wikipedia, the free encyclopedia)

Pearls – The Birthstone of June – Part 7

History

Pearl hunting

A 14th-century piece of clothing used by Kuwaiti divers searching for pearls in the Persian Gulf

The ancient chronicle Mahavamsa mentions the thriving pearl industry in the port of Oruwella in the Gulf of Mannar in Sri Lanka. It also records that eight varieties of pearls accompanied Prince Vijaya’s embassy to the Pandyan king as well as king Devanampiya Tissa’s embassy to Emperor Ashoka.  Pliny the Elder (23–79AD) praised the pearl fishery of the Gulf as most productive in the world.

For thousands of years, seawater pearls were retrieved by divers in the Indian Ocean in areas such as the Persian Gulf, the Red Sea and the Gulf of Mannar. Evidence also suggest a prehistoric origin to pearl diving in these regions. Starting in the Han Dynasty (206 BC–220 AD), the Chinese hunted extensively for seawater pearls in the South China Sea. Tanka pearl divers of twelfth century China attached ropes to their waists in order to be safely brought back up to the surface.

When Spanish conquistadors arrived in the Western Hemisphere, they discovered that around the islands of Cubagua and Margarita, some 200 km north of the Venezuelan coast, was an extensive pearl bed (a bed of pearl oysters). One discovered and named pearl, La Peregrina pearl, was offered to Philip II of Spain and then gifted to his wife Mary I of England. According to Garcilasso de la Vega, who says that he saw La Peregrina at Seville in 1607, this was found at Panama in 1560 by a slave worker who was rewarded with his liberty, and his owner with the office of alcalde of Panama.

Margarita pearls are extremely difficult to find today and are known for their unique yellowish color. The most famous Margarita necklace that anyone can see today is the one that then Venezuelan President Romulo Betancourt gave to Jacqueline Kennedy when she and her husband, President John F. Kennedy paid an official visit to Venezuela.

Before the beginning of the 20th century, pearl hunting was the most common way of harvesting pearls. Divers manually pulled oysters from ocean floors and river bottoms and checked them individually for pearls. Not all mussels and oysters produce pearls. In a haul of three tons, only three or four oysters will produce perfect pearls.

British Isles

Pearls were one of the attractions which drew Julius Caesar to Britain. They are, for the most part, freshwater pearls from mussels. Pearling was banned in the U.K. in 1998 due to the endangered status of river mussels. Discovery and publicity about the sale for a substantial sum of the Abernethy pearl in the River Tay had resulted in heavy exploitation of mussel colonies during the 1970s and 80s by weekend warriors. When it was permitted it was carried on mainly by Scottish Travellers who found pearls varied from river to river with the River Oykel in the Highlands being noted for the finest rose-pink pearls. There are two firms in Scotland that are licensed to sell pre-1998 freshwater pearls.

Pearl farming

A pearl being extracted from an akoya pearl oyster. See also: Oyster farming

Today, the cultured pearls on the market can be divided into two categories. The first category covers the beaded cultured pearls, including akoya, South Sea and Tahiti. These pearls are gonad grown, and usually one pearl is grown at a time. This limits the number of pearls at a harvest period. The pearls are usually harvested after one year for akoya, 2–4 years for Tahitian and South Sea, and 2–7 years for freshwater. This perliculture process was first developed by the British biologist William Saville-Kent who passed the information along to Tatsuhei Mise and Tokichi Nishikawa from Japan. The second category includes the non-beaded freshwater cultured pearls, like the Biwa or Chinese pearls. As they grow in the mantle, where on each wing up to 25 grafts can be implanted, these pearls are much more frequent and saturate the market completely. An impressive improvement in quality has taken place in the last ten years when the former rice-grain-shaped pebbles are compared with the near round pearls of today. In the last two years large near perfect round bead nucleated pearls up to 15mm in diameter have been produced with metallic luster.

The nucleus bead in a beaded cultured pearl is generally a polished sphere made from freshwater mussel shell. Along with a small piece of mantle tissue from another mollusk (donor shell) to serve as a catalyst for the pearl sac, it is surgically implanted into the gonad (reproductive organ) of a saltwater mollusk. In freshwater perliculture, only the piece of tissue is used in most cases, and is inserted into the fleshy mantle of the host mussel. South Sea and Tahitian pearl oysters, also known as Pinctada maxima and Pinctada margaritifera, which survive the subsequent surgery to remove the finished pearl, are often implanted with a new, larger beads as part of the same procedure and then returned to the water for another 2–3 years of growth.

Despite the common misperception, Mikimoto did not discover the process of pearl culture. The accepted process of pearl culture was developed by the British Biologist William Saville-Kent in Australia and brought to Japan by Tokichi Nishikawa and Tatsuhei Mise. Nishikawa was granted the patent in 1916, and married the daughter of Mikimoto. Mikimoto was able to use Nishikawa’s technology. After the patent was granted in 1916, the technology was immediately commercially applied to akoya pearl oysters in Japan in 1916. Mise’s brother was the first to produce a commercial crop of pearls in the akoya oyster. Mitsubishi’s Baron Iwasaki immediately applied the technology to the south sea pearl oyster in 1917 in the Philippines, and later in Buton, and Palau. Mitsubishi was the first to produce a cultured south sea pearl – although it was not until 1928 that the first small commercial crop of pearls was successfully produced.

The original Japanese cultured pearls, known as akoya pearls, are produced by a species of small pearl oyster, Pinctada fucata martensii, which is no bigger than 6 to 8 cm (2.4 to 3.1 in) in size, hence akoya pearls larger than 10 mm in diameter are extremely rare and highly priced. Today, a hybrid mollusk is used in both Japan and China in the production of akoya pearls.

Cultured Pearls were sold in cans for the export market. These were packed in Japan by the I.C.P. Canning Factory (International Pearl Company L.T.D.) in Nagasaki Pref. Japan.

(Information from Wikipedia, the free encyclopedia)

Pearls – The Birthstone of June – Part 6

From other species

A shell of the Indian volute, Melo melo, surrounded by a number of pearls from this species

Conch pearl pendant

Biologically speaking, under the right set of circumstances, almost any shelled mollusk can produce some kind of pearl. However, most of these molluskan pearls have no luster or iridescence. The great majority of mollusk species produce pearls which are not attractive, and are sometimes not even very durable, such that they usually have no value at all, except perhaps to a scientist or collector, or as a curiosity. These objects used to be referred to as “calcareous concretions” by some gemologists, even though a malacologist would still consider them to be pearls. Valueless pearls of this type are sometimes found in edible mussels, edible oysters, escargot snails, and so on. The GIA and CIBJO now simply use the term ‘pearl’ (or, where appropriate, the more descriptive term ‘non-nacreous pearl’) when referring to such items and, under Federal Trade Commission rules, various mollusk pearls may be referred to as ‘pearls’, without qualification.

A few species produce pearls that can be of interest as gemstones. These species include the bailer shell Melo, the giant clam Tridacna, various scallop species, Pen shells Pinna, and the Haliotis iris species of abalone. Pearls of abalone, or paua, are mabe pearls, or blister pearls, unique to New Zealand waters and are commonly referred to as ‘blue pearls’. They are admired for their incredible luster and naturally bright vibrant colors that are often compared to opal. Another example is the conch pearl (sometimes referred to simply as the ‘pink pearl’), which is found very rarely growing between the mantle and the shell of the queen conch or pink conch, Strombus gigas, a large sea snail or marine gastropod from the Caribbean Sea. These pearls, which are often pink in color, are a by-product of the conch fishing industry, and the best of them display a shimmering optical effect related to chatoyance known as ‘flame structure’.

Somewhat similar gastropod pearls, this time more orange in hue, are (again very rarely) found in the horse conch Triplofusus papillosus.

The second largest pearl known was found in the Philippines in 1934 and is known as the Pearl of Lao Tzu. It is a naturally occurring, non-nacreous, calcareous concretion (pearl) from a giant clam. Because it did not grow in a pearl oyster it is not pearly; instead the surface is glossy like porcelain. Other pearls from giant clams are known to exist, but this is a particularly large one weighing 14 lb (6.4 kg).

The largest known pearl (also from a giant clam) is the Pearl of Puerto, also found in the Philippines by a fisherman from Puerto Princesa, Palawan Island. The enormous pearl is 30 cm wide (1 ft), 67 cm long (2.2 ft) and weighs 75 lb.

More about Pearls in Part 7.

(Information from Wikipedia, the free encyclopedia)

Pearls – The Birthstone of June – Part 5

Types of Cultured Pearls

A blister pearl, a half-sphere, formed flush against the shell of the pearl oyster.

Keshi pearls, although they often occur by chance, are not considered natural. They are a byproduct of the culturing process, and hence do not happen without human intervention. They are quite small, typically only a few millimeters. Keshi pearls are produced by many different types of marine mollusks and freshwater mussels in China. Keshi pearls are actually a mistake in the cultured pearl seeding process. In seeding the cultured pearl, a piece of mantle muscle from a sacrificed oyster is placed with a bead of mother of pearl within the oyster. If the piece of mantle should slip off the bead, a pearl forms of baroque shape about the mantle piece which is entirely nacre. Therefore, a Keshi pearl could be considered superior to cultured pearls with a mother of pearl bead center. In the cultured pearl industry, the resources used to create a mistaken all nacre baroque pearl is a drain on the production of round cultured pearls. Therefore, they are trying to improve culturing technique so that keshi pearls do not occur. All nacre pearls may one day be limited to natural found pearls. Today many “keshi” pearls are actually intentional, with post-harvest shells returned to the water to regenerate a pearl in the existing pearl sac.

Tahitian pearls, frequently referred to as black pearls, are highly valued because of their rarity; the culturing process for them dictates a smaller volume output and they can never be mass-produced because, in common with most sea pearls, the oyster can only be nucleated with one pearl at a time, while freshwater mussels are capable of multiple pearl implants. Before the days of cultured pearls, black pearls were rare and highly valued for the simple reason that white pearl oysters rarely produced naturally black pearls, and black pearl oysters rarely produced any natural pearls at all.

Since the development of pearl culture technology, the black pearl oysters Pinctada margaritifera found in Tahiti and many other Pacific islands including the Cook Islands and Fiji are being extensively used for producing cultured pearls. The rarity of the black cultured pearl is now a “comparative” issue. The black cultured pearl is rare when compared to Chinese freshwater cultured pearls, and Japanese and Chinese akoya cultured pearls, and is more valuable than these pearls. However, it is more abundant than the South Sea pearl, which is more valuable than the black cultured pearl. This is simply because the black pearl oyster Pinctada margaritifera is far more abundant than the elusive, rare, and larger south sea pearl oyster Pinctada maxima, which cannot be found in lagoons, but which must be dived for in a rare number of deep ocean habitats or grown in hatcheries.

Black pearls are very rarely black: they are usually shades of green, purple, aubergine, blue, grey, silver or peacock (a mix of several shades, like a peacock’s feather).

Black cultured pearls from the black pearl oyster – Pinctada margaritifera – are not South Sea pearls, although they are often mistakenly described as black South Sea pearls. In the absence of an official definition for the pearl from the black oyster, these pearls are usually referred to as “black pearls”.

The correct definition of a South Sea pearl – as described by CIBJO and GIA – is a pearl produced by the Pinctada maxima pearl oyster. South Sea pearls are the color of their host Pinctada maxima oyster – and can be white, silver, pink, gold, cream, and any combination of these basic colors, including overtones of the various colors of the rainbow displayed in the pearl nacre of the oyster shell itself.

South Sea pearls are the largest and rarest of the cultured pearls – making them the most valuable. Prized for their exquisitely beautiful ‘orient’ or lustre, South Sea pearls are now farmed in various parts of the world where the Pinctada maxima oysters can be found, with the finest South Sea pearls being produced by Paspaley along the remote coastline of North-Western Australia. White and silver colored South Sea pearls tend to come from the Broome area of Australia, while golden colored ones are more prevalent in the Philippines and Indonesia.

A farm in the Gulf of California, Mexico, is culturing pearls from the black lipped Pinctada mazatlanica oysters and the rainbow lipped Pteria sterna oysters. Also called Concha Nácar, the pearls from these rainbow lipped oysters fluoresce red under ultraviolet light.

More about Pearls, the birthstone of June, in Part 6 of this series.

(Information from Wikipedia, the free encyclopedia)

Pearls – The Birthstone of June – Part 4

Imitation pearls

Some imitation pearls (also called shell pearls) are simply made of mother-of-pearl, coral or conch shell, while others are made from glass and are coated with a solution containing fish scales called essence d’Orient. Although imitation pearls look the part, they do not have the same weight or smoothness as real pearls, and their luster will also dim greatly.

Gemological identification

A well-equipped gem testing laboratory can distinguish natural pearls from cultured pearls by using gemological X-ray equipment to examine the center of a pearl. With X-rays it is possible to see the growth rings of the pearl, where the layers of calcium carbonate are separated by thin layers of conchiolin. The differentiation of natural pearls from non-beaded cultured pearls can be very difficult without the use of this X-ray technique.

Natural and cultured pearls can be distinguished from imitation pearls using a microscope. Another method of testing for imitations is to rub two pearls against each other. Imitation pearls are completely smooth, but natural and cultured pearls are composed of nacre platelets, making both feel slightly gritty.

Value of a natural pearl

Pearl tiara of Empress Eugénie (1853) featuring 212 natural pearls, Louvre, Paris.

Fine quality natural pearls are very rare jewels. Their values are determined similarly to those of other precious gems, according to size, shape, color, quality of surface, orient and luster.

Single natural pearls are often sold as collectors’ items, or set as centerpieces in unique jewelry. Very few matched strands of natural pearls exist, and those that do often sell for hundreds of thousands of dollars. (In 1917, jeweler Pierre Cartier purchased the Fifth Avenue mansion that is now the New York Cartier store in exchange for a matched double strand of natural pearls Cartier had been collecting for years; at the time, it was valued at US$1 million.)

The introduction and advance of the cultured pearl hit the pearl industry hard. Pearl dealers publicly disputed the authenticity of these new cultured products, and left many consumers uneasy and confused about their much lower prices. Essentially, the controversy damaged the images of both natural and cultured pearls. By the 1950s, when a significant number of women in developed countries could afford their own cultured pearl necklace, natural pearls were reduced to a small, exclusive niche in the pearl industry.

Origin of a natural pearl

Previously, natural pearls were found in many parts of the world. Present day natural pearling is confined mostly to seas off Bahrain. Australia also has one of the world’s last remaining fleets of pearl diving ships. Australian pearl divers dive for south sea pearl oysters to be used in the cultured south sea pearl industry. The catch of pearl oysters is similar to the numbers of oysters taken during the natural pearl days. Hence significant numbers of natural pearls are still found in the Australian Indian Ocean waters from wild oysters. X-ray examination is required to positively verify natural pearls found today.

Read more about Pearls in Part 5 of this series!

(Information from Wikipedia, the free encyclopedia)