Jewelry is seldom made from only pure gold, because pure gold is soft and bends too easily to maintain its shape. To avoid this problem, manufacturers mix gold with other metals. The resulting alloys are stronger and more wear-resistant than pure gold and can also be used to give the metal other colors, including pink, red, green and white.
In its natural state, gold is bight yellow. But jewelers also manufacture white gold, an alloy that mixes pure gold with copper, nickel and zinc.
White gold is somewhat harder than yellow gold, and some people prefer it because it compliments the look of their diamond.
The amount of gold content in a piece of gold jewelry is its karatage. Pure gold is called 24 Karat gold, of 24K. The gold content of less-than-pure gold is labeled in fractions of 24. For example, 14 Karat gold, or 14K, is 14/24 pure, meaning that 58.5% of the metal is gold. The rest is usually copper and silver. In the United States, the lowest karat gold that can be marketed as gold is 10K. The most popular variety is 14 Karat.
Jewelry does not have to be marked with its karatage, but most of it is. If there is a Karat quality stamped on the jewelry, a manufacturer’s registered trademark must be stamped right next to it. This means that the manufacturer is standing behind the claim as to the piece’s gold content. Always look for a karat mark and a trademark on gold jewelry. Make sure these marks are stamped on the body of the piece, not just on a clasp or hinge.