“Watches 101”

“Watches 101”What’s the best way to store a watch?
What’s a “movement”?
What is the legal definition of a Swiss watch?
Which leads to the question: What is a Swiss movement? They have a ready answer, of course:
What does the word “Geneve” on a watch mean?
What’s the difference between a mechanical movement and a quartz movement? 
What does 17-jewel movement mean?
What does the word “chronometer” mean?
Who is the COSC and what do they do?
What’s a “chronograph”?
What do the letters “T” and “O” mean on my watch?
It is possible that this comes from the French word for gold, Or, is it true that tritium is radioactive? 
Is there such thing as a completely waterproof watch?
What does “Shock Resistant” mean?
Is it true that only a diamond will scratch a sapphire crystal face?
What’s the best way to store a watch?
Storing a luxury watch properly requires a little extra care. Diamonds and other gemstones are hard enough to scratch metal jewelry and to mar the surfaces of other stones they come in contact with. Store diamond and/or gold watches in their own individual soft cloth pouches, place them in a jewelry box that has separate compartments for each piece or store them in their original box.What’s a “movement”? 
A movement is the mechanism that actually calculates the passage of time–the “guts” of the watch, if you will. Like the engine and transmission of a car, watch movements are so fundamental to the quality of the watch that they are often manufactured by separate companies, or by the same company in a different factory. The movement is also the part of the watch which is usually covered by a warranty–much like the “engine and drivetrain” warranties that come with new cars.

What is the legal definition of a Swiss watch? 
As the universally-acknowledged manufacturers of the world’s best watches, the Swiss are understandably rather persnickety about what watches qualify as “Swiss.” To protect the integrity of their good name, several organizations have formed with the specific intention of regulating quality and defining standards for the industry. The Federation of the Swiss Watch Industry has produced a list of “Verordnung Swiss Made” rules that state that a Swiss watch must:

  • Have a Swiss movement that
  • Was set into its case in Switzerland
  • By a manufacturer of Swiss origin.

Which leads to the question: What is a Swiss movement? They have a ready answer, of course:
It must have been assembled in Switzerland under the supervision of a Swiss factory and the parts of the movement that are Swiss in origin must constitute at least 50% of the movement’s total value. Movements that meet these exacting requirements earn the right to be stamped with the word “Swiss.” Sometimes the stamp will instead say “Suisse,” “Swiss Quartz,” “Swiss Made,” “Produit Suisse,” or “Fabrique en Suisse.” These all mean the same thing. However, if the case is not of Swiss origin, then this inscription cannot be visible–it must be concealed by the case. However, the case may be stamped with the words “Swiss Movement” to indicate that it’s Swiss on the inside, if not the outside. In the case of the reverse–a non-Swiss movement in a Swiss case, only the words “Swiss Case” are permitted.

What does the word “Geneve” on a watch mean?
Just as Geneva is a more specific location than Switzerland, the designation “Geneve” is a more exacting mark of prestige given to watches by the Bureau de controle des Montres de Geneva. To qualify, in addition to matching all the above criterion for a Swiss watch, it must have had one of its major manufacturing steps take place within the Canton of Geneva. The theory is that at least 50% percent of the manufacturing costs will have been incurred “locally,” protecting the trade and ensuring quality assembly.

What’s the difference between a mechanical movement and a quartz movement?
Mechanical movements are what most people think of when they talk about the fine art of watch making–a precise, intricate system of tiny gears and springs which use mechanical energy to operate. These watches have a mainspring, which is wound either by hand or by “automatic movement” (self winding). The spring power is then transferred to the hands of the watch via a precise timing mechanism known as a balance.

A quartz movement is a simpler, less expensive timing mechanism which regulates time by sending an electric current from a battery to a tiny quartz crystal, which vibrates at precise and predictable rates–32,768 cycles per second to be exact. Quartz movements are superbly accurate and reliable. Because they can be mass-produced, quartz movements are used in everything from clock radios and digital watches to some very fine timepieces. However, what is gained in efficiency is lost in elegance, according to some epicureans.

Interestingly enough, the first quartz watch, introduced by Seiko in 1969, cost over a thousand dollars!

What does 17-jewel movement mean?
In spring-powered mechanical watches, conservation of energy is practically an art form. To reduce friction, many of the spaces between gears are set with tiny synthetic gem crystals, which resist temperature changes better than metal and hold lubricant much longer.

What does the word “chronometer” mean?
Strictly speaking, anything that measures time is a chronometer (chronos = time, meter = measure). An hourglass or a sundial is technically a chronometer. However, in modern watchmaking the term “chronometer” is a specific designation of accuracy, assigned only to high-quality watch movements that have been tested by the COSC.

Who is the COSC and what do they do?
The Control Officile Suisse de Chronometers is a Swiss testing laboratory that certifies watches, or rather their movements, as “chronometers.” Each movement is individually tested over a 15-day period in different positions and temperatures, and passes only if it shows a loss of fewer than five seconds per day. Watches that have certified movements will usually be stamped with an inscription that says “Chronometer,” “Certified Chronometer,” or “Superlative Chronometer Officially Certified.”

What’s a “chronograph”?
By definition a chronograph “records time.” In modern watches this refers to a stopwatch function of some sort.

What do the letters “T” and “O” mean on my watch?
The letter “T” on the face of a watch stands for tritium, the greenish-white substance on the hands and numbers that glows in the dark. The letter “O” means that the indices on the dial are made of gold.

It is possible that this comes from the French word for gold, Or, is it true that tritium is radioactive?
Although tritium is a radioactive substance, the amount of radiation from tritium-coated watch faces is less than 25milliCuries, which isn’t even enough to penetrate the watch case or crystal.

Is there such thing as a completely waterproof watch?
Not really–in fact it’s not even a legal term in the US anymore, and for good reason. Even deep-sea submarines have maximum depths beyond which they cannot safely travel. That’s because deeper water means higher water pressure, and eventually water pressure will break the windows. Watches are rated for “water resistance,” which is an evaluation of how much water pressure the moisture seals can withstand. Most watches are rated to 50 meters, which is more than most of us will ever need. Sport and diving watches are often rated to 200 meters or more. Ironically, humans can only safely dive to about half that depth, and extremely high depth ratings are more an indicator of craftsmanship and status than actual utility. Water resistance is also measured in ATM, or atmospheres. One atmosphere is equivalent to 10 meters.

What does “Shock Resistant” mean?
Shock resistance is an American government standard of durability which means that the watch can survive a drop of three feet onto a wooden floor.

Is it true that only a diamond will scratch a sapphire crystal face?
Not quite. Another sapphire or ruby will scratch it. Also remember that scratch-proof is not hatter-proof. A sapphire crystal is remarkably durable, but far from impervious. It’s best to treat a quality watch like any other piece of finely-crafted jewelry.


Nine Shiny Facts About the Metal Silver

Nine Shiny Facts About the Metal Silver

January 24, 2014 by KIDS DISCOVER

SilverIt’s a precious metal found in lots of jewelry, but silver has plenty of everyday uses in electronics, medicine, paint, photography, currency, clothing, and more. Here are some facts you probably didn’t know about silver … .

Name: Its name comes from the Anglo-Saxon seolfor, but silver’s chemical symbol, Ag, is based on its Latin name, argentum.

Industry: Silver conducts heat and electricity better than all other elements, which is why it’s used in things like solar panels, electrical circuits, and rear window defoggers.

Heat: Silver melts at 1,763.2 degrees Fahrenheit, and it boils at 3,924 degrees Fahrenheit. So yeah, go ahead … you can stir soup with the good silverware.

Tarnish: That dark stuff that appears on silver and makes it need polishing is actually silver sulfide, a compound formed when silver interacts with sulfur in the air … or in eggs. Which is why some people don’t use good silverware with eggs or mayonnaise.

Coins: Until 1964, all United States dimes, quarters, half-dollars, and dollar coins contained 90 percent silver. So keep your eyes peeled when you get change at the market, because every now and then you can still find a real silver coin.

Bendiness: After gold, silver is the easiest metal to work with — you can stretch it into superfine wire or pound it into superthin foil (would you believe 150 times thinner than paper?).

Weather: Silver can make it rain! When silver iodide is dropped onto clouds in a process called “seeding,” it often provokes a rainfall.

Medicine: Silver is great at killing bacteria, which is why it’s sometimes used in wound dressings at burn units. And bacteria don’t adapt to silver’s germicidal properties the way they become immune to antibiotics.

Hygiene: You know what else bacteria do? They cause B.O. That’s why some fancy athletic clothing contains tiny silver fibers, which reduce or eliminate smells. But rubbing earrings or spoons under your arms in the morning really won’t help.



Jewelry Metals 101: Most Commonly Used Jewelry Metals

Jewelry Metals 101: Most Commonly Used Jewelry Metals

Jewelers, both professional and amateur, have used just about every type of metal in existence in their creations. As new alloys and metals are adapted to jewelry making, such as titanium and stainless steel, they are also eagerly embraced and worked into beautiful creations for men and women. While fashion trends using unique and trendy metals come and go, three jewelry metals have stood the test of time and continue to have a strong presence in modern jewelry.  They are Gold, Silver, and Platinum.

These three metals and the alloys that utilize them are referred to as the Noble Metals.  Noble Metals have four properties in common.

  1. They are precious metals and are also used as currency (a store of value) because of their intrinsic value.
  2. They are found worldwide, but not in large enough quantities to render them less valuable.
  3. Noble Metals have properties that lend themselves to jewelry making, including malleability and corrosion resistance.
  4. These metals are considered beautiful, sensuous, and glamorous, which increases their appeal. Because of all of these properties, the Noble Metals – gold, silver, and platinum – are frequently used in jewelry making.


Coveted for its beauty, gold has long captivated the human psyche and is considered the most sensuous metal. Jewelry designers and makers find gold easy to work with and prefer it to other metals because it never tarnishes. Gold is perhaps the most workable metal, which is another reason designers enjoy working with it. A single ounce of gold can be stretched into a thread more than 50 miles long or rolled flat into a sheet that covers 100 square feet in area!

Another reason gold is coveted by both consumers and designers is that it lasts indefinitely, especially if properly cared for. Recent studies show that gold originated in the far reaches of the universe billions of years ago and arrived on earth in its infancy. It does not oxidize or corrode and only a handful of rare acids or hot chlorine bleach can damage gold. Gold can also be reused by melting down old gold objects and reforming the gold into new pieces. For example, old coins and broken pieces of jewelry can be melted down and reused to make a brand new piece of gold jewelry.

Gold Alloys

Despite gold’s desirable properties, it does have one significant drawback. It is soft, which means it wears easily. By mixing gold with other metals, or alloying it, gold is made stronger, which makes it durable enough to wear more often without experiencing wear. A variety of metals are commonly used to alloy gold, including silver, copper, nickel, iron, zinc, tin, manganese, cadmium, and titanium. Along with enhancing gold’s strength, alloying gold with other metals changes some of gold’s other properties as well. This is why some gold alloys stain people’s skin or cause an allergic reaction. The reaction is not caused by the gold itself, but by the other metals it is mixed with.

While pure gold is also used in jewelry making, it dents and shows wear easily, which is why most people choose not to wear 100% gold jewelry on a regular basis. When discussing gold and its alloys, the term karat is used to indicate the purity of the gold (Not to be confused with carat, which is a unit of measurement used to describe gemstone weight). Pure gold, which contains no other metals, is termed 24 karat gold. A gold alloy that is 50% gold and 50% other metals is 12 karat gold because it is only half pure gold. Alloys used in jewelry making range from 9 karat gold, which is approximately 37% gold, to 24 karat gold, and are required to be stamped and hallmarked according to purity. A newer alloy becoming popular on the jewelry scene is made of 99% gold and 1% titanium, allowing the alloy to retain nearly all of its gold color while providing improved durability.

Gold Alloy      
Karat Parts Gold Percent Gold Other Marks
24 24/24 100% 1000
18 18/24 75% 740
14 14/24 58.33% 585
12 12/24 50% 500
10 10/24 41.60% 416
Colored Gold

Mixing gold with different metals changes the color of the gold. For example, mixing copper with gold makes the gold darker yellow, while adding nickel plus zinc or other silver metals produces white gold. Contrary to popular belief, white gold contains no silver, which softens gold and gives it a green tint. Gold alloys also come in colors, including green, red, and blue.

Colored Alloys
Gold Color  Alloys
White 10% to 20% nickel, plus copper, tin, and sometimes platinum or manganese
Green Silver, sometimes cadmium and zinc
Red or Pink Copper
Yellow Silver and copper
Blue Iron
Gold Terminology

When discussing gold’s purity, or what percentage is pure gold, the laws are fairly strict in the U.S. To be labeled as a specific karat, a gold item must be within three parts per thousand of the karat marking for solid pieces and seven parts per thousand for pieces containing solder. Pieces that fail to meet this criterion must be labeled with a lower karat designation. When labeling jewelry and other gold items for sale, you cannot call an item solid gold unless it truly is 24 karat and if you refer to an item as gold, you must designate what karat the gold is.

The term “new gold” does not mean that the gold was recently mined. It means that the gold has been carefully refined to current gold standards. “Old gold,” on the other hand, comes from melting down old jewelry, coins, and other gold items. This old gold may be a slightly lower karat weight than the original gold depending on how much solder was used in the original jewelry pieces. Impurities in old gold pieces cause a variety of headaches during casting, including bubbles, so old gold is often sent for refinement rather than being melted down by your local jeweler and recast into a new item.

Gold solder, which is used to join pieces together, is actually sold based on its color not its gold content. Because the solder needs to have a lower melting point than the pieces it is joining, it is mixed with metals that have lower melting points than gold. The solder is matched to the gold pieces for an attractive look. Though this poses no problems for the owner of the current jewelry item, melting down this piece with its solder in the future will reduce the karat of the gold.

Less Than Solid Gold

With solid gold selling for more than $1,250 per ounce (as of September, 2014), many jewelry makers look for alternative ways of giving their customers the look and feel of gold without the hefty price of solid gold. This is often done by coating pieces made from less expensive metals with thin coats of gold. Items that are made this way are referred to as gold overlay pieces.

When shopping for these pieces there are two distinct methods of overlaying the gold that you need to be aware of. The first is gold filled. Pieces that are gold filled have a minimum of 5% gold applied to the base metal. They are classified based on how much gold is overlayed and the karat of the gold. For example, if a piece is marked 1/20 14K G.F., it means that the piece has a 14 karat gold layer that comprises 1/20 of the weight of the piece. The second type of gold overlay, rolled gold plate, is similar, but the gold can be as thin as 1/40 of the weight. It is also stamped by fineness and content, 1/40 14K RGP. Gold platings are the thinner and less expensive of the two types of gold overlays. The gold is a few thousandths of an inch thick, at best, and wear off easily.

The care of gold overlay pieces is quite different from the care of solid gold pieces because of the fact that the gold is layered on top of another metal. As previously mentioned, the gold on these pieces wears off over time and you cannot use a polishing wheel on these items because it will remove the overlay and potentially ruin the item.

You can learn more about how gold is quoted and priced here.


With its illustrious history, silver has been more highly valued than gold at various times throughout the years. Long used as a medium of exchange, its name is synonymous with money. Today, silver has found many new uses including photography, batteries, auto glass defogger, and magnetic strips, just to name a few.

Silver’s most outstanding feature is its luster. This Noble Metal is not without its drawbacks though. The main drawback for silver is that it tarnishes. The term tarnish is used to denote a layer of corrosion that forms over some metals, including silver, when they undergo chemical reactions. The chemical reaction that causes silver to tarnish requires a compound called hydrogen sulfide. Silver jewelry encounters hydrogen sulfide in the air you breathe every day, which is why silver tends to tarnish if left out where it is exposed to this compound on a regular basis.

Storing these items in protective pouches or containers where they are exposed to less hydrogen sulfide reduces the amount of tarnish on silver, which means less you can spend less time removing tarnish from your silver jewelry. There are a number of ways to remove tarnish from silver pieces, including silver polish and do-it-yourself methods using common household items, so you do not have to shy away from silver pieces because of the tarnish. Silver jewelry does require more care than some other precious metals, because of the fact that it tarnishes.

Silver is more abundant and much less expensive than gold or platinum, which are additional reasons why it is a popular metal for jewelry; however, it is more difficult to work than gold, because it conducts heat so well. This is why beginning jewelry makers often learn how to solder on silver. Once they gain control of soldering on this highly conductive metal, they find it much easier to control the heat when moving up to gold.

Silver Alloys

Silver is also commonly alloyed with other metals because, like gold, pure silver is soft and easily damaged. Adding harder metals improves the durability of silver, allowing jewelry designers to design pieces that are beautiful and strong enough to wear every day. The most common silver alloy is sterling silver. Sterling silver is 92.5% silver. The remaining 7.5% is comprised of one or more other metals. A substantial portion of this 7.5% is often copper because it increases the hardness of the sterling silver.

The term Mexican silver applies to silver that is used as currency in Mexico and is typically comprised of 95% silver and 5% copper. While the copper increases its durability, it is used more for currency than jewelry. Typically even the silver jewelry made in Mexico is crafted from sterling silver.  You can learn more about silver markings, definitions, and terminology here.

In the U.S., coin silver contains 90% silver and 10% copper. You do not usually see coin silver used in jewelry. Britiannia silver contains a minimum of 95.84% silver, making it a more valuable alloy than sterling. While this may be used in jewelry, it is not common. There are a variety of additional silver alloys used worldwide, including a South American alloy made of 80% silver that does not tarnish. Jewelry makers stamp silver pieces with the code that denotes which alloy of silver it is. For example, 925 is used to designate sterling silver and 958 is used for Britannia silver. When shopping for silver jewelry inspect the piece carefully to determine which alloy was used.

Other Types of Silver Jewelry

While sterling silver is the most common type of silver used in jewelry making, there are some additional alloys that should be mentioned. Electrum, for example, is a naturally occurring alloy of silver and gold that was popular with the ancient Egyptians. Because electrum occurs naturally in nature, the ration of silver to gold varies with each piece.

Niello is a black mixture of silver, copper, and lead. It is used more like an enamel, so you do not typically see jewelry made entirely of niello. It is used as an inlay on etched or engraved metal or to fill in designs. Like electrum, niello was popular with the Egyptians, who used the mixture during the Iron Age.

While all of these silver alloys actually contain at least some silver, some metal names can mislead you into thinking the metal contains silver. Nickel silver or German silver, for example, are alloys of nickel, zinc, and other metals. These metals look like silver, hence the name, but they do not actually contain any silver. The same is true of quicksilver, which is the ancient term given to mercury due to its appearance. While mercury does resemble liquid silver, it does not contain silver and is not seen in jewelry because it is harmful to your health.


Platinum is the rarest and most expensive of the Noble Metals. Its unsurpassed holding power and durability make it a highly coveted, premium jewelry metal. Platinum is incredibly durable and does not tarnish, which is why it is often used for engagement and wedding rings.

Though platinum has been found in various objects as far back as 700 BC, its use in jewelry is relatively modern. The main reason for this is that refining platinum proved difficult for a number of centuries because the metal has an extremely high melting point and is highly resistant to corrosion. The oldest recorded use of platinum is as an inlay in ancient Egypt. However, the Egyptians though it was a variation of electrum. Native Americans used platinum in small decorative objects for centuries. Platinum was unknown to Europeans until the Spanish settlers discovered it in Columbia. The Spanish called it platina, meaning little silver, and believed it was unripe gold and, therefore, unusable.

It was not until the eighteenth century that platinum was identified as a new metal and a researcher from Sweden figured out how to melt platinum with arsenic. Once individuals learned how to refine platinum they began to use it to decorate porcelain and to make laboratory equipment. The use of arsenic to refine platinum was extremely dangerous, which is why platinum did not gain popularity until the oxyhydrogen torch was invented in the mid 1800s.

Discoveries of platinum ore in several countries in the nineteenth century brought platinum to the attention of jewelry makers and platinum quickly became a symbol of wealth and celebrity status in the early 1900s. Stars like Greta Garbo and Cole Porter frequently appeared on film with platinum jewelry and accessories. It also became popular for setting exceptional gems. For example, the 530-carat “Star of Africa” diamond in the British royal scepter is set in platinum.

While platinum is still highly coveted in the jewelry industry, it is also used for a variety of industrial purposes. Today, platinum is commonly found in catalytic converters because of its ability to cause chemical reactions while remaining unchanged. In fact, half of the platinum mined in the U.S. and a quarter of the platinum mined worldwide is used for this purpose. The U.S. Bureau of Standards also uses platinum for weights because it never oxidizes and, therefore, remains the same weight forever.

Platinum Alloys

Though most people believe that the term platinum refers to one single type of metal, the truth is it is used to refer to a group of metals that share similar properties. The platinum group includes platinum, iridium, palladium, ruthenium, rhodium, and osmium. Platinum is the most abundant; however, it is not the only one of the group that is used for making jewelry. Rhodium is popular as a non-tarnishing plating for white gold, silver, and other platinum metals. Others from this group, including palladium and iridium, are alloyed with other metals or used alone to make jewelry. In fact, all but osmium are used for jewelry. The most common platinum alloys include 90% platinum and 10% iridium, or 95% platinum and 5% ruthenium. Ruthenium makes for the harder and stronger alloy.

Common Metallurgy Terms

  • Alloy: Mixing two or more metallic elements, especially to give greater strength or resistance to corrosion
  • Amalgamation: Purifying gold by mixing it with mercury.
  • Cementation: To surround a metal with a substance that will react with the metal under heat. Silver is parted from gold by cementation with salt.
  • Cupellation: A means of separating gold and silver from other metals and impurities. The ore is heated in a “cupel,” (a ceramic cup,) which absorbs the impurities.
  • Distillation: Metals with a low boiling point, like mercury, are vaporized to separate them from other metals.
  • Noble Metals: Metals that resists corrosion and oxidation.
  • Smelting: To melt an ore to separate and refine the metals within it.
  • Water Concentration: Washing ore causes the heavier metals to stay behind where they can be recovered.


Jewelry Metals 101: Most Commonly Used Jewelry Metals

50 Surprising Facts You Never Knew About Gold

50 Surprising Facts You Never Knew About Gold

1. The word “gold” comes from the Old English word “geolu,” meaning yellow.

2. There is more steel created per hour than there has been gold dug up throughout history.

3. Around 161,000 tons of gold have been mined by humans.

4. Gold can be found beneath the earth on all seven continents.

5. It is believed that around 80% of earth’s gold is still buried underground.

6. There is an estimated total of 10 billion tons of gold in the world’s oceans. That is 25 tons of gold for every cubic mile of seawater.

7. The world’s first gold vending machine was unveiled in May 2010. Located in an ultra-luxury hotel in Abu Dhabi, the vending machine itself is covered in 24-carat gold.

8. Most western economies’ currencies were on the gold standard until 1961.

9. Switzerland was the last country whose currency was tied to gold. 40% of a Swiss Franc was backed by gold until Switzerland joined the IMF in 1999.


10. The gold held at Fort Knox is accounted for by the United States as an asset valued at $44.22 per ounce.

11. As of December 31, 1941 Fort Knox held 649.6 million ounces of gold.

12. Today, Fort Knox  holds about 147.3 million ounces.

13. The size of a standard gold bar is 7″ by 3 and 5/8″ by 1 and 3/4″

14. Alchemists believe they can change ordinary materials, such as lead, into gold.

15. A carat was originally a unit of mass based on the carob seed used by ancient merchants.

16. The most expensive gold coin in the world is the 1933 Double Eagle, which was sold at Sotheby’s in New York in 2002 for $7.59 million.

17. Elvis Presley owned three cars manufactured by Stutz Motor Company, in which every part that is normally chrome was converted to gold.

18. Former Tyco International CEO Dennis Kozlowski bought a gold-threaded shower curtain worth $6,000.

19. A noble metal, gold is prone neither to rust nor tarnish and does not form an oxide film on its surface when coming into contact with ai

20. There are 92 naturally occurring elements found in the earth’s crust. Gold ranks 58th in rarity.

21. The chemical symbol for gold is Au, which is derived from the Latin word “aurum,” which means “shining dawn.”

22. Absolutely pure gold is so soft that it can be molded with the hands.

23. The melting point of gold is 2,063 degrees Fahrenheit.

24. Gold is a great conductor of electricity.

25. Gold is the most malleable and ductile pure metal known to man.

26. An ounce of gold can be beaten into a sheet covering 100 square feet.

27. In 1869, two Australians unearthed the world’s largest nugget of gold, the “Welcome Stranger,” which measured 10 by 25 inches before it was melted down.

28. The largest nugget still in existence is the “Hand of Faith,” found in 1980 in Australia. It is currently on display at the Golden Nugget Casino in Las Vegas.

29. A gold nugget found in the earth can be three to four times as valuable as the gold it contains because of its rareness.

30. The heaviest modern gold bullion coin is Austria’s Philharmonic. In 2004, the coin, which has a weight of 1,000 ounces (31.1 kilograms or 69 troy pounds or 828 troy ounces) and a diameter of 15 inches, was dubbed the world’s largest gold coin by Guinness World Records.

31. In 2007, Canada made a 100 kilogram (3,217 troy ounce), 0.99999 gold coin with a face value of $1,000,000.

32. Pure gold does not cause skin irritations.

33. Some sufferers of rheumatoid arthritis receive injections of liquid gold to relieve pain.

34. Olympic gold medals were pure gold until 1912.

35. An ounce of gold can be drawn into a wire 60 miles long.

36. Two thirds of the world’s gold comes from South Africa.

37. India is the world’s largest consumer of gold today.

38. South Asian jewelry is generally more pure than western jewelry, comprised of 22 carat gold rather than 14 carat.

39. Gold is the state mineral of California and Alaska.

#-ad_banner_2-#40. 90% of the world’s gold mining has been done since the discovery of gold at Sutter’s Mill in California in 1848.

41. During the California gold rush, some speculators paid more for an ounce of water than they received for an ounce of gold.

42. South Dakota and Nevada produce more gold than any other states.

43. Scientists believe that gold can be found on Mars, Mercury, and Venus.

44. The visors of astronauts’ helmets are coated in a very thin, transparent layer of gold (.000002 inches) that reduces glare and heat from sunlight.

45. The Aztec word for gold, “teocuitatl,” was translated by Europeans as meaning “excrement of the gods.”

46. According to the legend of El Dorado (the gilded one), an Andean chief who was covered in gold dust would make offerings of gold into a mountain lake.

47. Evidence suggests that around 5,000 B.C., gold and copper became the first metals to be discovered by man.

48. King Croesus of Lydia created the first pure gold coins in 540 B.C.

49. When Franklin Roosevelt raised the price of gold from $20.67 to $35 in 1934, the dollar immediately lost 40% of its value.

50. Henry VIII, Diocletian and Nero were infamous gold debasers, mixing other metals into gold coins and decreasing their value.


12 Fun Coin Facts


12 Fun Coin Facts

Thursday, July 13, 2017 3:31:37 PM PST8PDT

Coin collecting can be a serious business, but it also has its fun and fascinating side. Here are a few things you might not know.

The Constitution Only Allows Coins, Not Paper Money

The Founding Fathers didn’t trust paper money, so they didn’t authorize it. It took an act of Congress in 1862 to print paper money for permanent circulation, and except for brief periods, some types remained redeemable in gold or silver until 1971, when the last U.S. Notes were discontinued.

The U.S. Dollar was Based on a Spanish Coin

The U.S. didn’t start minting its own coins until 1792. Until then, the Spanish silver 8-real coin, made in Mexico City (also known as “pieces of eight”), was so common that it was used as the basis for the value of the dollar. It remained legal tender in the U.S. until the mid-1800s.

A “Bit” Was a Real Denomination—More or Less

That same Spanish silver coin could easily be cut into eight parts (giving it its colloquial name) for smaller transactions. Those pieces were called bits, hence the expression “two-bits,” which was commonly used to describe one-quarter (2/8ths) of a dollar.

So Was the Eagle

The 10-dollar gold eagle, half-eagle and quarter-eagle coins were denominations specified in the Coinage Act of 1792. The double eagle $20 gold coin was created by that name in 1849.

All U.S. Coins Were Originally Gold, Silver, or Copper

Coins originally had worth of their own, since they were made of specific amounts of precious or semi-precious metals. When the value of those metals exceeded the coins’ worth, alloys and non-precious metals were substituted. Today’s circulating coins contain no gold or silver.

There Are No Pennies in U.S. Coinage

The coin representing 1/100th of a U.S. dollar is a cent, not a penny. The term penny came from European settlers who used the word to describe a small unit of currency in their native countries, but it has never been an official term in the U.S.

There Were 2-Cent and 3-Cent U.S. Coins Once

When the U.S. started minting coins in 1792, a dollar bought a lot more than it does today, so a few cents were all you needed to buy everyday items like food and sundries. That made 2- and 3-cent coins practical. Two-cent coins were discontinued in 1873 and 3-cents in 1889.

A Nickel Wasn’t Always a Nickel—Or Made of Nickel

We’ve always had the dime, but original 5-cent coins were called half-dimes and were made of silver. The small, thin coins were hard to use and easily counterfeited, and were replaced by a copper-nickel coin in 1873.

All U.S. Coins Bear Two Mottos

Federal law dictates that all U.S. coins carry the mottos “In God We Trust” and “E Pluribus Unum.”

Many Coins Are Worth Millions

In 2013, a 1794 “Flowing Hair” silver dollar sold at auction for over $10 million. 1913 Liberty Head nickels have sold for as much as $5 million. Pennies (OK, 1-cent coins) haven’t cracked the million-dollar mark yet, but a 1943 steel Wheat Cent can bring as much as $110,000.

Counterfeiting Used to be a Capital Offense

Because early coins were more crudely made, they were relatively easy to fake, so the 1792 Coin Act made counterfeiting or defacing coins punishable by death.

Billions of Dollars Are Just Lying Around

An estimated $10 billion in coins is held in U.S. homes. Another 58 million is left behind on airplanes worldwide, according to one estimate.

Coin collecting (numismatics, to be formal) has been a popular hobby as far back as ancient kings and queens, giving it the appellation “The Hobby of Kings.” As you learn more about the lore of coins, we’re sure you’ll agree that it’s a fun, fascinating activity with many rewards.




    • The Commission on Presidential Debates relies on coin flips to determine whether the Republican or Democratic candidate gets to answer first.
    • The one-cent piece flipped by Asa Lovejoy and Francis Pettygrove to determine what the city of Portland would be named is on permanent display at the Oregon Historical Society.
    • Press operators at the US Mint spot check each batch of new coins.
    • In the sixteenth century, the Spaniards established mints in Mexico and South America to coin the gold and silver mined there.
    • Football Hall of Famer Turk Edwards saw his career come to a premature end when he twisted his knee while walking back to the sideline after calling the opening coin flip.
    • David’s coin features an image called “Seated Liberty” on the front. It was designed by assistant engraver Christian Gobrecht.
    • If David were alive and flipping coins in 1855, he’d be able to choose from eight different U.S. coins: the dollar, the half dollar, the quarter dollar, the dime, the half dime, the silver three-cent piece, the cent, and the half cent.
    • The United States minted the first dollar coin in 1794. Today, a 1794 “flowing hair” dollar can fetch upwards of $10 million at auction.
  • The tiny ridges found on the edges of U.S. quarters and dimes are known as reeding.


7 Interesting Facts about Gold Eagle Coin

7 Interesting Facts about Gold Eagle Coin

Gold Eagle CoinThe official bullion coin of the United States of America, the Gold Eagle is highly sought after by both investors and numismatists alike. Combining high quality all American precious metal, beautiful design and excellent reputation, this is one of the most popular coins in the world.

Let’s learn 7 interesting facts about this all American bullion coin.

1. The gold Eagle coin is the only coin type which is guaranteed by the United States government. American Eagle gold coins are guaranteed to have a specific content, weight, purity level, and metal quality involved, and this is backed by the US government.This backing eliminates any questionable factors and allows you to know exactly what you are getting for your money.

2. A Gold Eagle coin has a design which is very similar to double eagle gold coins. Both show Lady Liberty, and include an eagle in the design. They both carry the currency value of the coin, as well as the date minted.

3. Until 1992, all gold Eagle coin purchases had a minting date that was reflected in Roman Numerals. From 1992 on these numbers are stamped using Arabic numerals instead. That year was when the US Mint implemented the number changes and switched from Roman to Arabic numbers for these coins.

4. The Gold Eagle coin has value as legal currency. This is also true with most American Buffalo gold bullion coins as well. Each coin will have a face value, normally from five dollars to fifty dollars, and even if the price of gold drops down to one dollar an ounce these coins are still worth the value minted on them.

5. The Gold eagle was first introduced in 1986, after it was authorized by the Gold Bullion Coin Act of 1985. This act allowed gold coins which have a legal currency value as well as a value for the precious metals included.

6. The United States Gold Eagle coin can only include gold that is sourced from the US, and these coins can not include any metal from foreign sources in the minting process. This is a legal requirement, and cannot be eased for any reasons.

7. The American Eagle gold bullion coin is composed of 22 Karat gold and contains about 10% of copper and silver alloys making them more scratch resistant compared to their 24 karat counterparts. These coins are available in 4 different denominations creating excellent investors’ choice.




7 Interesting Facts about Gold Eagle Coin

10 fun facts about coins everyone should know…..

When did coins replace stones, cattle, and other early forms of money?

Metal in many shapes and sizes was used for money long before coins started making the rounds.  Today we know about two groups of people who, thousands of years ago, started making objects similar to what we call coins.  They stamped pieces of metal with weights (values) and other marks.  This way they didn’t need to weigh the metal each time it was used to buy something.

Who were these first coin creators?  We’ve long known that around 600–700 B.C., people from Lydia (part of what is now Turkey) started stamping the royal emblem of a lion’s head onto pieces of electrum.  They got this alloy of gold and silver from the banks of Lydia’s rivers.  And recently, we’ve discovered that even earlier (about 1000 B.C.) people in China made bronze coins.

What name should you call a coin collector?

Numismatist!  (Pronounced new-miss-ma-tist.)  This tongue-twister of a word makes a rich addition to your vocabulary.  It means “someone who studies and collects things that are used as money, including coins, tokens, paper bills, and medals.”

Who was the first person to collect coins?

Just think of the month of August, and it’s easy to remember this answer.  The earliest recorded coin collection belonged to Augustus Caesar, the first emperor of Rome.  He lived from 63 B.C. to A.D. 14, and the eighth month of our year is named after him.

Not only did Augustus keep adding coins to his collection, but he also gave them as gifts.  Following his lead, many of the Roman emperors who ruled after Augustus also had large coin collections.  The hobby became even more popular during the Middle Ages, when wealthy individuals and royal families built awesome collections.

How much new change does the United States Mint make each year?

Each year, the United States Mint makes between 14 billion and 20 billion circulating coins.  These new pennies, nickels, dimes, quarters, half dollars, and dollar coins are all made at the Philadelphia and Denver mints.

How long does the average coin last, and what happens to worn-out coins?

Most coins can circulate for about 25 years before they become too worn to be used anymore.  That’s a long time when you consider that the average dollar lasts for only 18 months.

The United States Mint recycles worn-out coins it receives from a Federal Reserve Bank.  The Mint then sends any usable metal that’s recovered to a fabricator, who turns it into coinage strips for new coins.

What is green slime, and why should I fear it?

Green slime is as nasty as it sounds!  As a collector, it’s one of your worst enemies.  It will take a valuable coin and turn it into a sticky, worthless mess.  Green slime is a chemical that’s used to make plastics softer, and its real name is as horrible as what it does to coins: polyvinylchloride (PVC).

How does PVC attack coins?  By lurking in some of the flips and other holders used to store coins.  Over time, the sticky film spreads from the container to your coin, eating into its surface.  You NEVER want to store your coins in anything made with PVC!

What’s worth more—a coin or its metal?

Nearly always, circulating coins are worth more than the metal they are made from.  In fact, coins—especially old-dated ones—can be worth a great deal more if they are in “mint condition.”

When should you not add a bright and shiny coin to your collection?

When it’s been buffed or whizzed!  A buffed coin is one that’s been polished to make it look like an uncirculated or proof coin.  A whizzed coin has been wire brushed or burnished, often on a wheel, for the same reason.  The problem with buffing and whizzing is that they wear down the coin’s original surface, reducing its value.


What makes a coin valuable?

Age, rarity, condition, and precious metal all affect how much a collectible coin is worth.  The value of any one coin can be surprising.  For example, you can buy some Roman coins that are more than 1600 years old for less than $10.  But then there are some worn 1909 wheat pennies that sell for hundreds of dollars!

As a general rule, the harder a coin is to find and the more people who want it, the more it’s worth.  This is known as the law of supply and demand.  It holds true no matter what the collectible.

What kind of grades do coins get?

Not A’s, B’s, C’s or even F’s.  Coins have their own grading system, which describes how much—or how little—wear and tear they have.  U.S. coins are graded with a scale created by the American Numismatic Association (ANA), a non-profit group created in 1891 and chartered by Congress since 1912.  The lowest grade on this scale is About Good-3; the highest is Perfect Uncirculated-70.



Facts About Dental Gold

At Manhattan Gold & Silver, one of our biggest client bases comes from the dental industry. Not many people are familiar with the intricacies of gold use in a dental practice, but there are many interesting facets of dental gold and how it functions in the mouth.

The mouth is a tough environment for just about any substance. After all, the mouth’s purpose is to break down food. Gold is one of those unique materials that can stand up to the punishment the mouth dishes out. Gold is completely inert to all body chemistry, so it won’t corrode in the mouth. It’s also tough enough to stand up to chewing and biting, so it’s an ideal material to use in crowns, fillings, and bridgework.

However, because the mouth is such a tough environment, pure gold is not used in dentistry. As you may know, pure gold is extremely malleable – so 24k gold would likely become deformed in the mouth over time. As such, dental gold is usually a 16k alloy containing other metals such as palladium, silver, copper and/or tin. This fact combined with the small size of the dental implant means that any one crown or bridge is not worth that much in gold. The real money comes in when you can collect a bunch of these, but is usually only possible if you are a dentist.

Sometimes, when dental gold is brought to a refiner, it’s still stuck to the tooth. Techniques for removing the tooth vary, but popular methods include using a jewelers hammer or an overnight soaking in cola to loosen the bond and remove the gold.  We would melt and assay the material.

Today, fillings are more commonly made of other less expensive and/or cosmetically desirable substances like mercury amalgam or polymer compounds. However, gold is still the strongest and longest lasting material a dentist can use.  Amalgam we do not process because it contains mercury.



Materials Engineering: Little-known facts about precious metals

Materials Engineering: Little-known facts about precious metals

The melting points and densities of the so-called Noble Metals, coupled with their resistance to chemical attack, sets them apart from most other materials.

May 08, 2008

Edited by Jean M. Hoffman

Unless you work with precious metal (PM) frequently, your knowledge of these metals is probably limited. The 15-min discussion devoted to PMs in college materials-science classes likely did not do justice to the engineering value for these eight elements. If you did not know there were eight (No, titanium is not one of them.), read on to find out what your professor probably did not know either.

A precious metal is a rare metallic element of high economic value. PMs are also referred to as Noble Metals because they resist most types of environmental and chemical attack. One of the few chemical solutions that attacks them (with the exception of iridium) is aqua regia. Only copper and PMs are found in nature in their metallic state. All other metals are processed from minerals or ores into metals which are inherently unstable and have a tendency to revert to their more stable mineral forms.

PMs, as a group, have a set of physical and chemical properties that are unrivaled by many other materials. If PMs were more available (in both quantitative and economic terms), there would be far more applications overall. Though typical applications use only small amounts, PMs may be used in large quantities when there is no feasible substitute.

The eight PMs — gold (Au), silver (Ag), platinum (Pt), iridium (Ir), palladium (Pd), rhodium (Rh), ruthenium (Ru), and osmium (Os) — are conveniently grouped together in the periodic table. A subset of this group is called the Platinum Group Metals (PGM), which includes all but Au and Ag. Typically the PGMs are found combined together in rich ore. Chemical processing extracts the individual elements. The short supply (there are only a few major mining locations), economic value, and costly mining and extraction methods have raised the cost of these metals substantially.

In 2004, South Africa produced a total of 5 million troy ounces of Pt (70% of the world’s output) and 8 million troy ounces of PGMs (50% of the world’s output). It takes about a ton of rich ore to produce approximately 1 troy ounce of PGMs, at best. Some mines only produce PGMs on the level of 5 to 25 gm/ton of processed ore.


PM properties typically differ from those of conventional metals in two primary areas: melting point and density. The melting point (MP) for low-alloy steel is about 2,800°F with a density in the range of 7.8 gm/cm3; compare this to Ag, Au, and Pt, for example, with respective melting points of 1,764, 1,947, and 3,216°F and densities of 10.5, 19.3, and 21.5 gm/cm3. These features, coupled with their resistance to chemical attack, set PMs apart from most other materials. The range of applications for PMs are diverse and they serve in applications where other materials won’t work.

Electrical and thermal conductivity: Many of the PMs have excellent electrical and thermal conductivity. Silver has the distinction of having the highest room-temperature conductivity of the PMs, as well as the highest of all metals. It should be no surprise that copper is the metal more predominantly used for electrical wire instead of Ag because it costs much less.

Corrosion resistance: PMs form, in some cases, an almost imperceptible oxide film. Their use as plating materials are effective and very broad. Additionally, these metals and their alloys are used in cathodic-protection systems to protect large-scale systems from the effects of corrosion.

Catalysts: Pt, Pd, Rh and their various alloys are widely used catalysts in large and small chemical reactors such as vehicle exhausts. A rich solution “washed” onto a ceramic substrate can leave a catalytic surface. The surface can also be a robust construction of woven or knit wire that provides a large-scale surface for chemical production. These are the primary applications for PGMs. Pt-based catalysts have been used for nitric acid production for more than 100 years.

High temperature applications: Combined high MP temperatures and low reactivity at elevated temperatures is a key quality of PGMs. Steel melts at 2,800°F, while Pt, Rh, and Ir have MPs of 3,216; 3,560; and 4,429°F, respectively. Vessels made from Pt, Pt-Rh, and Ir are used in the making of fiberglass and silicon ingots, as well as for the melting of other high MP, reactive media. One clever application uses Pt and the zirconium oxide formed during powdered-metal spraying to produce a highly creep-resistant material even when heated close to its melting point. Zirconia-grain-stabilized (ZGS) platinum and Pt-Rh alloys have been used in the glass industry for many years. The addition of zirconium and its subsequent oxidation during metal spraying create a grain structure that limits grain growth and boosts high-temperature creep strength.

Thermocouple devices: Thermocouples made from Pt and Pt-Rh wire pairs are unparalleled at giving accurate and finer temperature measurements. Currently, wire producers are able to make wire diameters small to keep costs low.

High-temperature heating coils: A heating coil can obviously only go as high as the melting point of the material used to construct it. PGM alloys can survive repeated oxidation cycles that can reduce the life of the heating coil. The use of PGM alloys satisfies both the issue of high service temperature and the problem of long-term oxidation attack.

Spark-erosion resistance applications: The development and application of Pt and Ir alloys along with pure Ir (some combinations of PMs are patented) has resulted in spark plugs that last for more than 100,000 miles. Some manufacturers use ball-bearing fabrication equipment to make small Pt alloy spheres that are then resistance welded onto the plug to form the electrode pair. For the more critical applications on aircraft, short pieces of Ir rod-stock material are centerlessly ground to an exacting size and form and then installed in the spark plug. Additionally, electrical contacts with an extended operational life have been made from Pt and Pd strip stock for various devices by high-speed stamping of small crowned circular blanks.

Fuel-cell applications: The electrical output from the fuel cell is made by combining hydrogen (the fuel) and oxygen (from air) over a catalyst such as platinum.

Biocompatibility and radio-opacity: The medical devices produced from PMs include stents, marker bands for angioplasty devices, pacemaker wire, endoscopy tips, and special surgical tools. The material most commonly used is Pt (or alloys of Pt), except for dental applications which use Au and Pd. X-rays don’t easily pass through Pt, Au, and Ir because of their atomic absorption coefficients, as well as their high densities. Thus these materials typically show up as a white area on film or scanning device. This property, referred to as radio-opacity, coupled with their biocompatibility properties, lets doctors see the exact location of these materials when used within the human body.

Pharmaceutical use: Pt-based drugs have been in use to treat cancer for 30 years and are the widely accepted standard-course-of-treatment for testicular cancer. Gold has also been used for the treatment of prostate cancer, whereby small gold “seeds” are irradiated and injected into the cancer site to kill the cancer cells by the slow release of radiation.

Labware, equipment and related devices: Pt and Ag resist attack from many substances. As such, they are used as crucibles, electrodes, inoculating loops, ignition boats, and many other forms of labware. Because these materials are noble, the testing method is not skewed by contamination from the test equipment. Basic forms of material (wire, tube, sheet, and strip) can be fabricated into countless products for industrial use.

Photographic applications: At one time, the Eastman Kodak Co. was the single largest user of Ag in the world. Many films and photo papers used silver compounds as the light-sensitive emulsion. Pt and Pd compounds also were used to produce black and white printing paper, which was and still is considered by many to be the best paper for fine tonal reproduction. These prints are the most resistant to environmental attack.

Coinage, collector’s items, and jewelry: PMs have been used throughout history for currency and jewelry. Our ability to examine past cultures is due, in part, to the nobleness of these materials. They are able to survive hundreds or even thousands of years of concealment and burial and still be viable as a historical record. Jewelry accounts for the second largest demand of PMs. md

John C. Keefe previously worked as the manager of Manufacturing Engineering at Johnson Matthey (Precious Metals Div.) in West Chester, Pa., where he supervised engineering and fabrication of a range of products made from precious metals and their alloys.

Quick facts

A different weight measurement system is used for precious metals. The standard unit is the troy ounce. The troy ounce (to) is different than our common ounce, in that it has a mass of 31.1035 gm versus 28.350 gm for the standard (avoirdupois) ounce (32.1507 to = 1 kg). Even when referring to large amounts of precious metal, the quantity is still expressed in troy ounces.

Gold (Au) has the longest and most storied history of all the precious metals. It is the most malleable of metals and therefore can be worked with simple tools to form complex shapes. The metal’s low MP has made it one of the first metals that could be readily cast. Its excellent corrosion resistance, thermal, and electrical properties have made it a top design choice for many devices. The ability to plate gold in extremely thin layers still allows for more extensive application of the material. The cost of gold is constantly varying; currently it costs about $980/to.

Silver (Ag) has the best room-temperature electrical and thermal conductivity of all metals. The principal sources of Ag are as an associated element from the mining of copper, copper-nickel, Au, lead and, lead-zinc ores obtained from Canada, Mexico, Peru, Australia, and the U.S. Silver has found many applications primarily because of its lower melting point and ease of fabrication. Silver is the most available and least costly of the precious metals at $20/to.

Platinum (Pt) occurs naturally and is accompanied by small quantities of the other PGMs. It is a beautiful silvery-white metal that is malleable. The metal is extensively used in jewelry, wire, vessels for laboratory use, and in many valuable industrial products including thermocouples, medical devices, and anticancer drugs. It is also used for electrical contacts, corrosion-resistant devices, and in dentistry. Pt-cobalt alloys have powerful magnetic properties. One such alloy, made of Pt-23.3 wt.% Co, offers a maximum magnetic field strength almost twice that of AlNiCo V, a strong permanent-magnet material. Resistance wires made from Pt are used in the construction of high-temperature electric furnaces. Pt can be drawn into fine wire and then knit into fabric referred to as gauze. The gauze is then fabricated into a large catalytic surface. It has long been used in the process for producing sulfuric acid (H2SO4) and nitric acid (HNO3). The present cost for Pt is approximately $2,045/to.

Iridium (Ir) is the rarest precious metal and the densest material known. It is more difficult to mechanically work than any other face-centered cubic (FCC) metal. This has been attributed to a reduction in ductility caused by trace element impurities that cause a modification of the grain boundary behavior. Its high tensile strength at elevated temperatures and high MP, makes it viable for crucibles in crystal growing. Hot working is one of the few ways to reasonably work the metal. Precise dimensional cuts are difficult, but are best achieved from either grinding or wire-EDM. Iridium is the most resistant of all metals to corrosion; it is insoluble in mineral acids including aqua regia. Resistance to spark erosion has made this element popular for spark plug applications.

Palladium (Pd) is a steel-white metal which doesn’t tarnish in air but can be attacked by nitric and sulfuric acids. It has the lowest density and melting point of the PGMs. At room temperature the metal has the unique property of absorbing up to 900 times its own volume of hydrogen. Hydrogen readily diffuses through heated palladium and development of this property provides a means of purifying the gas. The metal and its alloys are used in dentistry, watch making, surgical instruments, catalytic converters, jewelry trade, and electrical contacts.

Rhodium (Rh) occurs naturally with other PGMs. It has a high reflectance and is hard and durable. Sputtering targets of Rh are used to make the reflective surface for automobile mirrors and other optical instruments. As a bulk metal, it is mostly used as an alloying agent to harden Pt and Pd. Such alloys go in furnace windings, thermocouple elements, and to make bushings for glass fiber production. The addition of Rh increases both the operation temperature and the mechanical properties of the material. Rhodium also serves in a range of catalyst applications and in alloys and coatings for jewelry. Rhodium has the current distinction of being the most costly precious metal at over $9,300/to.

Ruthenium (Ru) is a hard, white metal mainly used as an alloying agent for platinum. The addition of 0.1% ruthenium to titanium immensely improves the corrosion resistance. It is a versatile catalyst and can help promote the splitting of hydrogen sulfide. Pure Ru is a difficult material to work.

Osmium (Os) is used almost exclusively as an alloying agent and has the distinction of having the highest melting point of the precious metals. Certain forms (tetroxides) are highly toxic. Osmium tetroxide is used in forensic science as a stain for fingerprints, microscope samples, and DNA materials. The metal is lustrous, bluish-white, and extremely hard and brittle even at high temperatures.


Fun fact

The density of gold and platinum is almost twice that of lead, whose density = 11.34 gm/cm3. In most old western movies, and more recently in the George Clooney movie called Three Kings (1999), the “bad guys” are shown loading gold bars. This is a bit far-fetched because many of the bars at the sizes shown would weigh close to 80 or 90 lb. A saddlebag of these plus the rider would be too much for the horse, or a human, to carry. Most people don’t have the opportunity to actually lift a gold bar, so Hollywood perpetuates the myth.

Iridium’s high melting point and resistance to chemical attack makes it the preferred material for crucibles used in the production of high purity single crystals of various metal oxides used in a variety of applications. Photo courtesy of Johnsom Matthey.

The eight precious metals — gold (Au), silver (Ag), platinum (Pt), iridium (Ir), palladium (Pd), rhodium (Rh), ruthenium (Ru), and osmium (Os) — are conveniently grouped together in the periodic table.