gold alloy

A gold alloy is a mixture of pure gold and other metals, such as copper or silver, combined to enhance its strength, durability, or color. Since pure gold (24-karat) is soft and prone to scratching or bending, alloys make it more practical for jewelry and coins. The proportion of gold in an alloy is measured in karats; for example, 18-karat gold contains 75% gold. Alloying also allows for a variety of shades—from classic yellow to white or rose gold—by adjusting the types and amounts of other metals mixed with the gold.