The degree of purity of native gold

The degree of purity of native gold, bullion (bars or
ingots of unrefined gold), and refined gold is stated in
terms of gold content. “Fineness” defines gold content
in parts per thousand. For example, a gold nugget
containing 885 parts of pure gold and 115 parts of
other metals, such as silver and copper, would be
considered 885-fine. “Karat” indicates the proportion
of solid gold in an alloy based on a total of 24 parts.
Thus, 14-karat (14K) gold indicates a composition of
14 parts of gold and 10 parts of other metals.
Incidentally, 14K gold is commonly used in jewelry
manufacture.

“Karat” should not be confused with “carat,” a unit of
weight used for precious stones.