Moissanite Moe · Nov 11, 2026 · 2 min read
Moissanite vs Lab Diamond vs CZ: What's the Difference?
Moissanite is a lab-grown gemstone with more sparkle than diamond, a 9.25 hardness, and it passes a thermal diamond tester. Lab diamond is real diamond grown in a lab. CZ is cheap, soft, clouds within months and fails the tester. For jewelry you wear daily, moissanite gives diamond looks at a fraction of the price.
What is each one?
- Moissanite: silicon carbide. Found in a meteorite first, now grown in a lab. A gemstone in its own right.
- Lab diamond: carbon, same as mined diamond, grown in weeks instead of a billion years.
- Cubic zirconia (CZ): zirconium dioxide. A diamond look-alike, not a gemstone most jewelers take seriously.
Which one sparkles more?
Moissanite. It has a higher refractive index than diamond, so it throws more rainbow flashes ("fire"). Some people think it's too flashy. Most people buying iced jewelry want exactly that.
Which one lasts?
Hardness (Mohs): diamond 10, moissanite 9.25, CZ 8 to 8.5. Numbers aside, here's what happens in real life: CZ scratches, clouds and goes dull within months. Moissanite stays clear for life. Diamond too.
Which passes a diamond tester?
Diamond and moissanite pass a thermal tester. CZ fails. Full explanation: Does moissanite pass a diamond tester?
What do they cost?
For a 1 carat round stone, roughly:
- CZ: a few dollars
- Moissanite: tens of dollars
- Lab diamond: hundreds to over a thousand
- Mined diamond: thousands
That's why moissanite is the sweet spot for pieces you actually wear.
The part nobody tells you: the metal
Stone choice is half the story. Cheap jewelry puts any stone on plated brass, which turns skin green and tarnishes. Put moissanite on 925 sterling silver and the piece holds up like fine jewelry.
FAQ
Is moissanite better than CZ?
Yes, in every way that matters: harder, clearer for life, and it passes the tester.
Can a jeweler tell moissanite from diamond?
With a dual tester or a loupe, yes. With a basic pen tester, no.
Is lab diamond worth the extra money?
For an engagement ring, maybe. For a chain or earrings you wear every day, moissanite looks the same and costs far less.
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