18 Karat Gold
18 karat (18K) gold contains 18 parts gold and 6 parts other metals, making it 75% gold.
14 Karat Gold
14 karat (14K) gold contains 14 parts gold and 10 parts other metals, making it 58.3% gold.
10 Karat Gold
10 karat (10K) gold contains 10 parts gold and 14 parts other metals, making it 41.7% gold. 10k gold is the minimum karat designation that can still be called gold in the US.
STERLING SILVER is 92.5% pure silver and 7.5% other metals.