Moissanite vs lab-grown diamond
A lab-grown diamond is a real diamond: carbon, hardness 10, the same as a mined diamond. Moissanite is a different gem, silicon carbide, hardness 9.25, with more than twice the fire. Both are made in a lab. Lab-grown diamonds usually cost several times more than moissanite of the same size, and they come with grading reports from labs such as IGI or GIA.
Side by side
| Moissanite | Lab-grown diamond | |
|---|---|---|
| What it is | Silicon carbide | Diamond (carbon) |
| Made | In a lab | In a lab |
| Hardness (Mohs) | 9.25 | 10 |
| Dispersion (fire) | 0.104 | 0.044 |
| Grading report | Usually a GRA card | Usually IGI or GIA |
| Price at the same size | Lowest | Several times moissanite |
What they share
Both are grown in a lab, so neither needs a mine. Both are hard enough for an everyday engagement ring. Neither is an investment: plan to wear it, not to sell it.
Where they differ
A lab-grown diamond is chemically and optically a diamond, so it has a diamond's white sparkle and is graded on the diamond scales for color, clarity and cut. Moissanite has more color in its sparkle and is sold by size, with its carat given as diamond equivalent weight.
How to choose
If you want a diamond and your budget allows it, a lab-grown diamond gives you one for less than a mined stone. If you want the biggest, brightest stone for the money and you like extra fire, moissanite is the better buy.
Questions
Is a lab-grown diamond a real diamond?
Yes. The FTC treats lab-grown diamonds as diamonds, as long as the seller says they are lab-grown. Moissanite is not a diamond of any kind.
Which is more durable?
Lab-grown diamond is harder (10 vs 9.25). In daily wear both resist scratches well, and both can chip from a hard knock.
Which sparkles more?
Moissanite shows more rainbow color because of its higher dispersion. A lab-grown diamond shows a whiter sparkle.
More guides
- What is moissanite?
- Moissanite vs 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.