Most people in the US who buy their gold locally, or receive a piece of jewelry as a gift probably don’t give much thought to its quality because the US system for gold uses karats, i.e. 10k, 14k, 18k, etc. The number of karats equalling the gold purity.
Detectorists, however, frequently find gold jewelry from a variety of different countries, which can be confusing when trying to determine gold quality.
The European system for gold uses number designations which correspond to the percentage of gold content.
The following info may be helpful to you in determining the karatage of your foreign gold finds.
The European karat system for gold:
Number Karats % of Gold
333 8k 33.3%
375 9k 37.5%
417 10k 41.7%
500 12k 50%
585 14k 58.5%
750 18k 75%
875 21k 87.5%
917 22k 91.7%
999 24k 100%
(10k is marked “417” for 41.7% gold, 14k is marked “585” for 58.5% gold, etc…)
To determine karatage of a piece of jewelry, look for the quality mark. Pieces generally bear the stamp of their karatage based on the US or European system.
Note-Some antique jewelry may not have these marks, yet still be gold.
10 k is the lowest gold content that can be legally marked or sold as gold jewelry in the US.
9k is a popular karatage sold in England and other regions, and 8k is very popular in Germany.