Gold is a precious commodity that is used to manufacture coins, artifacts and jewelry. It also has health uses, such as in dental implants and crowns. The value of gold is measured by purity, which is determined by the number of other metals the gold contains. Gold dealers use several methods to evaluate the purity of gold, including the use of nitric acid. Typically, gold is offered in 10, 14, 18 and 24-carat choices, each representing a different level of purity.
A carat is a unit of measurement used to describe the purity of an element based on 24 whole parts. Jewelry that is entirely composed of a single element is considered 100 percent pure and is described as being 24-carat. However, gold that is 100 percent pure is typically too soft to be made into jewelry and is often mixed with another metal to ensure a durable structure.
Though 24-carat gold is the softest of all gold carats, it is still the most expensive gold available for purchase. 24-carat gold is defined as 100 percent pure. 18-carat gold is considered 75 percent pure because only 18 of its 24 parts are gold. Fourteen-carat gold is 58.3 percent pure, as 14 out of its 24 parts are made of gold, and 10-carat gold is 41.6 percent pure, with only 10 of its 24 parts consisting of gold.
Because 24-carat gold is pure, it is not combined with another type of metal, which is not the case for 18, 14 and 10-carat gold. Metals added to these gold carats are known as alloys, which can affect the price of the gold. Commonly used alloys include silver, copper, zinc, nickel, palladium and platinum. The price of gold jewelry is dependent in part on the kind of alloy it contains. In general, a platinum alloy is the most expensive because of its durability and purity.
Yellow, White and Rose
Differences exist in gold colors based on the alloy the gold contains. Yellow gold is typically 14 and 18-carat gold and has a deep orange tint. Zinc and silver are common alloys in yellow gold, which hardens the jewelry but preserves the rich color. White gold is also produced from 14 and 18-carat gold, but contains alloys such as silver, platinum and palladium, which dilutes the gold hue and creates a silver color that looks very similar to pure platinum jewelry. Rose gold is less common than yellow and white gold and contains a copper alloy that gives the gold a pink-rose hue. It is generally produced from 10 and 14-carat gold.