Gold is the world's most ancient and most coveted metal. Wherever it was mined or traded, it always represented wealth and power. The earliest known gold jewelry came from the Sumer civilization around 3000 BC, in an area that we now know as southern Iraq. Other ancient masterpieces were created across Europe, the Middle East, Asia, and South America. Gold's beautiful color and malleability inspired craftsmen to create ornaments and jewelry by developing techniques like chain-making, alloying, pounding, and lost-wax casting.
Pure gold is generally considered too soft to make into everyday jewelry. It bends, scratches, and wears away with friction. Even in ancient times, gold was frequently alloyed with other metals to keep its shining glow but with added strength, durability, and a range of colors. White gold's look is achieved by alloying gold with nickel, silver, or palladium. Red gold is created by alloying gold with copper. Most yellow gold contains varying amounts of nickel, copper, and zinc.
The purity of gold (or percentage of pure gold in an alloy) is measured in karats (kt). Karat should not to be confused with a "carat" (ct), the unit of weight for diamonds. Here's a quick chart to break down the conversion:
24 karat gold is currently very popular in Asia, where it has the Chinese name chuk kam. 10 karat gold is the lowest amount jewelers in the United States can call real gold. Most popular in the West is 14 or 18 karat gold, which is warmly lustrous and finely workable but strong enough to wear every day.
When gold is weighed, it is generally measured in grams (g) or ounces (oz). All real gold jewelry must have its karatage clearly stamped on it.
Gold is a mined metal, and sources have been found on literally every continent. But, until the California rush of 1848 (and the rushes that followed in Canada and Australia) gold was an extremely rare metal. Russian output accounted for 30-35 tons of world total gold of 75 tons by 1847. Now, the most productive gold mines are in South America, Africa, North America, and Australia.
Today, gold is used for everything from high tech semiconductors to gold crowns for teeth -- and of course, it is still one of the most desired jewelry metals everywhere. Right now, the world's mined gold equals more than 125,000 tons -- of that amount, 90% was mined after the California gold rush. While this increase is pretty amazing, what's even more incredible is that all the gold ever mined would form a cube only 19 meters per side.
Although platinum was used in ancient Egypt and by the South American Incas, it was not as valued as gold. Until modern jewelers' tools were developed, platinum was more difficult to work with because it has an extremely high melting point. In the early 1900s, the best jewelry designers -- Cartier, Tiffany, Faberge -- began to create intricate and amazingly durable designs using platinum, and its popularity soared. It was the precious metal chosen for mounting some of the world's great diamonds, including the Hope Diamond, which is on display at the Smithsonian.
During World War II, the US government declared platinum a strategic metal, so white gold and silver were substituted for all white metal jewelry. After the war, platinum returned to the jewelry market and has had periods of great popularity. Platinum is very fashionable now; interest in the precious, coolly lustrous white metal has grown rapidly over the last five years.
Platinum is the heaviest of the precious metals. Platinum is a family group of six metals: platinum, palladium, rhodium, ruthenium, iridium, and osmium.
Like gold and silver, platinum is considered a "noble metal," which means that it will not oxidize or corrode. Unlike gold and silver, platinum in its pure state is extremely strong and durable and doesn't need to be alloyed. It will not wear down over the years or tarnish, as gold and silver can. When platinum is scratched, it does not lose material to the extent that other precious metals do.
Like the diamond, platinum is rare. 10 tons of ore are needed to produce every ounce of platinum, and processing the metal into jeweler's quality platinum takes five months. In the United States, all platinum jewelry is either 90% platinum and 10% iridium or 95% platinum and 5% ruthenium. It is always stamped "IRIDIPLAT," "900pt," or "pt 900" when it is 90% platinum and "PLAT," "950pt" or "pt950" when it is at least 95% platinum.
The two major sources of platinum in the world are South Africa and Russia. 90% of South Africa's platinum is reserved for industrial uses. Platinum is used in many essential modern goods. It is an important component of gasoline, fertilizers, fiber-optic cables, anti-cancer drugs, explosives, and pacemakers; all catalytic converters in automobiles depend on it.
Platinum is fifteen times more rare than gold, and fifty times more rare than silver. It is so rare, in fact, that all the platinum ever mined in the world would fit into the average-size living room.
Archeologists' tests indicate that humans have created objects and ornaments out of silver since 4000 BC, just after their discoveries of gold and copper. Silver is now the most plentiful of the precious jewelry metals. Like platinum and gold, silver is malleable, scarce, and noble (non-corroding). It also has a bright, lovely luminosity that makes it increasingly desirable as a jewelry metal.
In ancient times, silver was mined in areas surrounding the Mediterranean -- especially in the countries now known as Turkey and Greece -- as well as in parts of Asia. When polished, this lustrous white metal achieves an almost glassy shine, so it was used to create sacred items, jewelry, and the ancient luxury item we call the mirror.
In its pure state, silver was considered too soft to retain a crafted shape or design, so it was alloyed with other metals for increased strength. Today, silver is most frequently alloyed with copper. The best known alloys are Sterling (92.5% silver) and Britannia (95.8% silver). Another standard for jewelry is 80% silver. Pure or alloyed, silver tends to tarnish. The dark yellow or black patina can easily be removed with commercial cleaners or silver polishes. Some other alloys of silver are being used in the industry now as well. Alloys that make up 95% silver and 5% alloy (commonly paladium) which will resist tarnish more effectively. Port City Jewelers NSCD Diamond Collection uses 950 Silver! This allows the metal to be worn daily without worry of the metal tarnishing. It also keeps the metal hypoallergenic.
Silver coins were minted and used as trade currency as long as four thousand years ago; but, silver was quite a scarce commodity until Spanish conquistadors discovered rich sources in Central and South America. Spain profited hugely from the exploitation of these mines, which produced far more than sources in Europe and Asia.
North America burst onto the silver scene with the 1859 discovery of the famous "Comstock Lode" in Nevada. During its productive years, the Comstock made the United States the world's largest producer of silver. In the 20th century, the US was upstaged from this position by Mexico and Peru, which still produce a significant percentage of the world's silver.
Many countries -- including England and the United States -- used silver as their currency standard for hundreds of years. In 1900, the US Congress passed the Gold Standard Act, permanently shifting the nation's financial focus from silver to gold.
Silver still has many uses in modern society. It is valued in industry for its conductivity and honored in medicine as a powerful antiseptic. The art of photography could not have been developed without this precious metal. Naturally, cooly shining silver is forever loved in fine and affordable jewelry designs.