What is the purity of 24K gold? Pure gold that contains no other metals is 24 carat. Lower caratages have less gold in them; for example, 18-carat gold has 75% gold and 25% other metals, usually ...

Diamonds and other gemstones are weighed in metric carats: one carat is equal to 0.2 grams, about the same weight as a paperclip. (Don’t confuse carat with karat, as in “18K gold,” which refers to ...