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Gold
Gold has long been known as one of the most valuable metals available to us. Pure gold is the term used to describe 24 karats of gold. The karat measures how much gold a particular piece contains. For example, the gold alloy used most in jewelry is 14 karat. That means 14 parts of gold were mixed with 10 parts of other metals.

Silver
Silver and gold must both be combined with other metals in order to be used in jewelry. These metals are simply too soft to be used on their own. Sterling silver is a common term in pieces today. This labeling means a particular piece contains 92.5 percent pure silver and 7.5 percent copper.

Platinum
A lesser known precious metal, platinum is nonetheless gorgeous to look at and wear. Jewelry made of platinum actually contains an allow of 90 percent platinum and 10 percent iridium or ruthenium. Platinum is one of the rarest of the precious metals. Because it is so rare, it is usually expensive.

Palladium
This is one of the more recently discovered precious metals. Palladium is very light. It is used mainly when a piece of metal jewelry is desired to be lighter in weight. When palladium is alloyed, it is generally in a formula of about 95.5 percent palladium, and 4.5 percent ruthenium.

Rhodium
Rhodium is often used with platinum. Rhodium is a very bright white metal and is ideal for plating jewelry.

Ruthenium
This is a precious metal that is often combined with other, more desired precious metals such as palladium or platinum, because those substances are generally fairly light. Ruthenium is a very hard metal. That's why this is such a popular choice among jewelers.

Iridium
Iridium is a white and heavy metal. Iridium is usually used in pen points and watches. It is a very brittle metal and is found naturally in platinum ore.

Osmium
Osmium is a gorgeous metal, that takes a bluish-white color. It, too, is found in platinum ore and often is combined with platinum and iridium in certain jewelry types.