Moissanite vs Diamond
Moissanite and diamond look alike at a glance, but they are different gems with different strengths. We make jewelry in both moissanite and lab grown diamond, so here is a plain, honest comparison to help you choose.
What Each Stone Is
Diamond is pure carbon. It can be mined, or grown in a lab; a lab grown diamond has the same chemical, physical and optical properties as a mined one.
Moissanite is silicon carbide, a mineral first found in a meteorite crater in 1893 by the French chemist Henri Moissan. Natural moissanite is far too rare for jewelry, so the moissanite you buy is grown in a lab. It is classed as a diamond simulant: it looks similar to diamond but is a different gem, and it should always be sold as moissanite.
Side by Side
| Moissanite | Diamond (mined or lab grown) | |
|---|---|---|
| Made of | Silicon carbide | Carbon |
| Hardness (Mohs) | 9.25 | 10 |
| Refractive index | About 2.65 to 2.69 | 2.42 |
| Dispersion (fire) | About 0.104, more than twice diamond | 0.044 |
| Refraction | Double | Single |
| Weight for the same size | About 9 to 10% lighter | Heavier |
| Price for the same size | Lowest | Lab grown: moderate. Mined: highest |
Sparkle and Look
Moissanite's higher refractive index and much higher dispersion make it look extremely bright, with strong rainbow-colored flashes, especially in sunlight and in larger stones. Diamond shows a whiter, more balanced mix of brilliance and fire. Neither is better; it depends on the look you love. If you want the classic diamond look, choose diamond. If you love colorful sparkle, moissanite gives you more of it.
Durability
Diamond is the hardest natural material, at 10 on the Mohs scale. Moissanite, at 9.25, is harder than every other gem commonly used in fine jewelry, and it is tough and chemically stable. Both are excellent for an engagement ring worn every day. Moissanite does not go cloudy over time; see does moissanite get cloudy?
Size and Carat
Because moissanite is lighter, it is usually labelled by diamond-equivalent size: a moissanite sold as "1 ct" is the size of a 1 ct diamond, about 6.5 mm across for a round. Always compare stones by their millimetre measurements; our size chart shows typical sizes for every shape.
Price
For the same size, moissanite costs a small fraction of a mined diamond and considerably less than a lab grown diamond. Neither moissanite nor lab grown diamond is an investment; buy the one you love wearing.
How to Tell Them Apart
Most people cannot tell by eye. A jeweler can: moissanite usually passes a basic thermal diamond tester but is flagged by a tester that also measures electrical conductivity, and under a loupe its double refraction can make facet edges look doubled. A gem lab can identify either with certainty. Read more in does moissanite pass a diamond tester?
Which Should You Choose?
- Choose moissanite for the most size and sparkle for your budget, in a stone hard enough for daily wear. Browse moissanite engagement rings.
- Choose a lab grown diamond for a real diamond with the classic diamond look, for far less than mined. Browse lab grown diamond engagement rings.
Still deciding? Read moissanite vs lab grown diamonds, is moissanite worth it? and the best diamond alternatives.
Quick Answers
Is moissanite a fake diamond?
No. Moissanite is a real gemstone in its own right. It is not a diamond, and an honest seller always describes it as moissanite.
Does moissanite sparkle more than diamond?
It shows more fire, the colored flashes, and is very bright. Diamond's sparkle is whiter. Many people prefer one or the other.
Will moissanite scratch?
Very rarely. At 9.25 on the Mohs scale it resists everyday scratches. Only diamond is harder among gems used in fine jewelry.
Do your moissanite pieces come with a certificate?
Every Bhumi Gems piece ships with a Bhumi Gems certificate of authenticity that states the stone and metal.
Your Next Step