Gold Alloys – What Is A Carat?

A Carat Is 1/24th By Weight

Don’t confuse the word “carat” as used for diamonds or other gemstones, when it is a unit of weight.
A carat as applied to gold alloys means a proportion by weight of one part in twenty-four, or 41.66 parts per 1000. The higher the carat value, the higher the proportion of gold in relation to the base metal content. Pure gold is therefore 24 carat.

Percentage by Weight

The following table shows typical “recipes” for different common gold alloys.

Percentages by Weight
Alloy Gold Silver Copper Zinc Nickel Palladium
9 Yellow 37.5 10 45 7.5 - -
9 White 37.8 0 40 10.4 11.8 -
14 Yellow 58.5 4 31.2 6.3 - -
14 White 58.5 0.5 27 7 7 -
18 Yellow 75 16 9 - - -
18 White 75 4 4 - - 17
22 Yellow 91.7 5.5 2.8 - - -
24 100 - - - - -
24 Carat