Gold Karat Rating Explained

Henryk Gudas has operated the U.S.-based design studio Gudas, Inc., since 1998. As an established jeweler, Henryk Gudas has worked extensively with gold, which is typically rated and measured in terms of “karats.”

The karat system is used because pure gold is too malleable to be a practical choice for jewelry. As a result, it is often combined with more common and less expensive “base metals” such as copper or zinc. These combinations of metals are referred to as alloys. The unit of purity for gold alloys is the karat, which is abbreviated as kt or K. One karat is equal to 1/24 part, meaning that a 24-karat gold item contains 100 percent gold. By contrast, a 6-karat gold alloy consists of 25 percent gold and 75 percent other metal(s).

Because gold is such a soft metal, 24-karat specimens are usually only used for display or in ceremonial capacities. The majority of gold objects are between 9-karat and 18-karat, but all gold sold as jewelry in the United States must have a minimum karat rating of 10.