Britannica Sources used in this answer

How do copper and silver change the color and hardness of gold alloys?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

A diagram showing the periodic table entry for gold, with the symbol Au, atomic number 79, atomic weight 196.96657, electron configuration, and labels for its properties as a solid transition metal with a face-centered cubic crystal structure. — gold The precious metal gold is a chemical element with the symbol Au. Its square on the periodic table details some of its properties, including its atomic weight, atomic number, and crystal structure.

Pure gold is exceptionally soft, making it unsuitable for prolonged handling or everyday use in items like jewelry, goldware, or coinage. To address this, it is commonly alloyed with other metals to increase its hardness and strength.12

Effects on Hardness

Because pure gold is too soft to resist wear, it is alloyed with metals such as silver and copper to provide the necessary durability. These additions significantly improve the material's structural integrity, making it practical for crafting durable jewelry and dental repairs.12

Effects on Color

The addition of silver and copper also alters the appearance of gold:
* Color Variation: The color of gold alloys shifts from yellow toward white as the proportion of silver increases.1
* White Gold: When gold is alloyed with nickel, copper, and zinc, it produces white gold.1
* Silver Content: Alloys containing more than 70 percent silver appear white.1
* Yellow Gold: Most gold used in jewelry is alloyed with varying proportions of silver and copper to produce different shades of yellow gold.1