Jewelry is normally made from alloys, mixtures of two or more metals. Gold, for example, is alloyed (combined) with metals such as silver, copper and zinc to make it harder, to change its color and/or to reduce its cost. Platinum alloys are usually made by combining platinum with ruthenium, iridium, palladium, cobalt or copper.
When comparing fine jewelry prices, find out the platinum or gold content of the metal. It's called fineness-the amount of gold or platinum in relation to 1000 parts. For example, gold with a fineness of 750 has 750 parts (75%) gold and 250 parts of other metals.
An alloy containing 95% platinum has a fineness of 950.
In some countries, the karat is also used as a measure of gold purity. One karat is 1/24 pure, so 24 karat represents pure gold. Metal containing 75% pure gold is 18 karat (18K) gold.
24K is 99.9% Gold
22K is 91.6% Gold
18K is 75.0% Gold
14K is 58.3% Gold
10K is 41.6% Gold
Other Jewelry Metal Terms
Budget-priced jewelry is made with the following metal types.
Gold filled (GF): Composed of a layer of gold mechanically bonded to a base metal using heat and pressure. In the United States, the layer must be at least 10K gold and 1/20th of the total weight of the object.
Gold overlay or rolled gold plate (RGP): Same as gold filled except the gold layer is thinner. It can be from 1/20th to 1/40th of the total weight of the object.
Gold Electroplate (GEP): Plating with a gold layer that is at least 7/1,000,000 of an inch thick. The object is dipped in a gold plating solution while an electrical current is used to bond the gold particles of the solution to the metal surface. The thickness of the gold depends upon the amount and duration of the current.
Gold versus Platinum
The natural beauty of gold, along with its workability, high value and history has made it the world's most important jewelry metal. Nevertheless, it's facing strong competition from platinum.
In the 1920's and 30's, platinum was the preferred metal for engagement and wedding rings in America and Europe. This was because platinum can be thin and dainty, yet sturdy, resistant to wear and better at securing stones than gold. Then in World War II, the U. S. government declared platinum a strategic metal and banned its use in all non-military applications, including jewelry.
Because of strong consumer preference for platinum's neutral color, white gold was substituted for platinum. White gold is created from yellow gold by adding metals such as copper, zinc, silver and/or palladium. After the embargo was lifted, platinum did not regain its previous popularity in America because white gold was less expensive and easier to work with, and the public accepted it.
Platinum is again becoming the metal of choice for settings and wedding and engagement rings. Consumers are discovering that most platinum alloys are harder, denser, and more durable than 14K and 18K gold. In addition, the white metal compliments diamonds that are colorless. Unlike white gold, it does not need to be plated with rhodium to look white.
There are advantages to gold jewelry. Gold earrings and necklaces are more comfortable because they are lighter in weight than platinum if they're the same style. Gold has a distinctive yellow color, it cost less, and more jewelers are trained to work with it. Gold compliments the skin tone of some people more than white metals.
Geographic sources: In 1999, South Africa was the largest producer of gold, followed in descending order by the United States, Australia, Canada, China, Indonesia, Russia and Peru. Approximately 70% of the world's platinum is mined in South Africa, 20% in Russia, 6% in North America and the rest elsewhere.
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