What Does CZ Mean on Jewelry?

CZ stamped near a stone means Cubic Zirconia — an inexpensive, lab-grown crystal used to imitate diamonds. It's flawless-looking and affordable but far softer and denser than diamond, and it has little resale value. The stamp is the maker telling you the stone is a simulant, not a natural or lab-grown diamond.

What is a CZ piece worth?

A CZ mark means the stone is cubic zirconia, which has minimal resale value regardless of how convincing it looks.

How to verify a CZ stamp

To tell a CZ from a real diamond, use the Is My Diamond 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 CZ with every other mark side by side, see the full jewelry stamps and markings chart.

Frequently asked questions