What is moissanite?
Moissanite is silicon carbide (SiC), a gemstone first found in 1893 by the French chemist Henri Moissan in rock from Meteor Crater in Arizona. Natural moissanite is extremely rare, so all moissanite in jewelry is lab-created. It rates 9.25 on the Mohs hardness scale, harder than sapphire, and it shows more rainbow fire than a diamond. It is its own gem, not a diamond.
Where moissanite comes from
In 1893 Henri Moissan studied fragments of the Canyon Diablo meteorite from Meteor Crater, Arizona, and found tiny, very hard crystals. He first thought they were diamonds. They turned out to be silicon carbide, and the mineral was named moissanite in his honor.
Natural crystals are almost always microscopic, far too small to cut. Gem moissanite is grown in a lab from silicon and carbon, then cut and polished like any other gemstone. Lab-created moissanite has been sold as a jewelry stone since 1998.
Moissanite at a glance
| Property | Moissanite |
|---|---|
| Chemistry | Silicon carbide, SiC |
| Hardness (Mohs) | 9.25 |
| Refractive index | 2.65 to 2.69 |
| Dispersion (fire) | 0.104 |
| Specific gravity | About 3.22 |
| Optics | Doubly refractive |
| Heat | Stable to about 1,700°C (3,100°F) in air |
Is moissanite a diamond?
No. Diamond is pure carbon; moissanite is silicon carbide. They look alike at a glance, which is why moissanite is often worn in place of a diamond. When a stone is used that way, the US Federal Trade Commission calls it a diamond simulant, and a seller has to name it clearly. We always call our stones moissanite.
Why people choose it
- Hard enough for every day: steel tools cannot scratch it.
- More fire: it splits light into more color than a diamond does.
- Size for the money: a 6.5 mm moissanite costs a small fraction of a diamond of the same size.
- Made in a lab: no mining is needed to make the stone.
Questions
Is moissanite real?
Yes. Moissanite is a real gemstone made of silicon carbide. Gem moissanite is lab-created, because natural crystals are too small to cut. It is not a diamond, and we always sell it as moissanite.
Is moissanite natural?
Natural moissanite exists but is extremely rare and almost always microscopic. All moissanite used in jewelry is made in a lab.
How hard is moissanite?
9.25 on the Mohs scale. Only diamond, at 10, is harder among gems used in jewelry. Steel is about 5.5 to 7, so a knife or a file cannot scratch it.
Can moissanite break?
Yes. Any gemstone, diamonds included, can chip from a hard knock. Hardness is resistance to scratches, not to impact.
More guides
- Moissanite vs diamond
- Moissanite vs lab-grown diamond
- Moissanite carat and size
- What a GRA certificate means
- Will moissanite pass a diamond tester?
- Moissanite and silver care
By the moissaniteit team, Olivia Star Jewelry LLC, Florida. Updated 2026-10-11.