14K gold alloy is a blend of gold and other metals for use in jewelry and other decorative products. Pure gold, which is the 24K variety, is generally too soft to use in jewelry. Consequently, 14K gold is the most commonly used alloy in the United States.
Percentage of Gold in 14K Alloy
14K gold jewelry is comprised of 14 parts pure gold with 10 parts other metals. By weight, 14K gold is 58 percent gold with the balance in other metals.
Benefits to Using Alloys
Adding various metals to gold creates more durable, resistant jewelry. As gold is a more costly metal, combining it with other metals is usually cost-effective, as well.
Metals Used in Gold Alloys
Jewelers use metals such as copper, silver and nickel to create alloys, and the choice of metals affects the resulting color. The lower the karat number assigned to a particular alloy the less gold or yellow the alloy will appear. Alloys containing white metals such as silver, platinum, palladium, zinc and nickel create a white gold. The addition of copper will transform it to rose gold, while a blend of copper and white metals will result in green gold.
Stamping of Gold
All gold sold in the U.S. must by law be stamped with the alloy designation. In North America, a karat designation system is used. Gold that is 14K is 14/24 parts gold to alloy, or 58.33 percent gold. Jewelry manufactured in Italy is assigned a three-digit number known as the "fineness" number. The fineness number assigned to 14K gold is 583.
Using an Acid Test to Determine Karats
While gold alloys are harder than pure gold, they are more easily dissolved in acid. Jewelers utilize a chemical solution known as aqua regia, which is a combination of nitric and hydrochloric acids, to test gold. When nitric acid is added to 14K gold it dissolves.