Сведения о классификации золота по стандартам США; там же информация о его скупке (платят не очень-то много):
http://www.goldkit.com/Understanding-Gold.asp
In Europe gold is stamped according to its fineness. Pure gold is 1000 fine; 18k gold is 75% or 750 fine. Consequently, an 18k ring made in Europe would be stamped 750. Below is a chart of the most common karat markings.
US / Karats % of Gold Fineness
24 100% 1000
22 90% 900
18 75% 750
15 62.5% 625
14 58.33% 583
10 41.67% 417
9 37.50% 375
