What Does 18K Mean on Jewelry?

An 18K stamp means 18-karat gold: 18 parts gold out of 24, or 75% pure. It's the standard for fine and designer jewelry because the high gold content gives a deep, luxurious color, with just enough alloy to be wearable. The European equivalent stamp is 750.

What is a 18K piece worth?

18K is 75% gold, so it carries high melt value (~$72/gram at ~$3,000/oz) and a rich, warm color.

How to verify a 18K stamp

18K is premium and often imitated — scan the 18K mark with the Hallmark Reader and verify with the Is It Real? tool. Anyone can stamp a mark on metal, so a hallmark alone isn't proof — the fastest way to check is to photograph the stamp and run it through the free Hallmark Reader, then confirm the metal itself with the Is It Real? tool. For a full picture of what your piece is worth, get a free jewelry appraisal. To compare 18K with every other mark side by side, see the full jewelry stamps and markings chart.

Frequently asked questions