What Is Moissanite? The Complete Guide to the Gemstone
Moissanite is a gemstone made of silicon carbide. It is the stone most often chosen as an alternative to diamond. It sparkles brightly, it is hard enough to wear every day, and it costs a fraction of the price. This guide explains where moissanite comes from, how it is made, how it compares with diamond and what to look for when you buy it.
Where moissanite comes from
In 1893 the French chemist Henri Moissan was studying rock from the Meteor Crater area near Canyon Diablo, Arizona, and found tiny sparkling crystals. He first thought they were diamonds. In 1904 he identified them as silicon carbide, and the mineral was later named moissanite in his honour.
Natural moissanite is extremely rare. It has only been found as microscopic grains in meteorites and in a few rocks from deep in the earth, far too small to cut into jewelry. Every moissanite gemstone sold today is lab-created. Gem-quality moissanite reached the jewelry market in 1998, after years of work on growing large, clear silicon carbide crystals.
How moissanite is made
Moissanite is grown as a crystal from silicon and carbon at very high temperatures. The crystal is then sliced and cut by hand into round, oval, pear, emerald and many other shapes, just like a mined gemstone. Because the growing conditions are controlled, moissanite is very clean inside and comes in colorless grades as well as colors such as blue, green and champagne. Read more in our colored moissanite guide.
Moissanite properties at a glance
| Property | Moissanite | Diamond |
|---|---|---|
| What it is | Silicon carbide | Carbon |
| Hardness (Mohs) | 9.25 | 10 |
| Refractive index | 2.65 to 2.69 | 2.42 |
| Dispersion (fire) | 0.104 | 0.044 |
| Specific gravity | about 3.22 | about 3.52 |
| Refraction | Doubly refractive | Singly refractive |
Figures from published gemological data, including GIA's original 1997 study of synthetic moissanite.
What those numbers mean when you wear it
- Hardness 9.25: only diamond is harder among gemstones. Moissanite resists scratches and keeps its polish, so it is well suited to an engagement ring worn every day. See our guide to moissanite durability.
- Higher refractive index: moissanite bends light more than diamond, which gives it a bright, lively look.
- Dispersion more than double diamond's: this is the "fire", the flashes of rainbow color. It is the easiest way to spot moissanite, especially in sunlight and in larger stones.
- Lower specific gravity: moissanite is lighter than diamond, so a moissanite and a diamond of the same size do not weigh the same. That is why moissanite is often described by its size in millimetres or by its diamond equivalent weight (DEW), the weight a diamond of the same size would have. Our moissanite and diamond size chart shows the millimetre size for each carat weight.
- Double refraction: light splits in two inside the stone. Under magnification you can see the back facet edges doubled when you look at an angle. Good cutters orient the stone to keep this out of the face-up view.
Is moissanite a diamond?
No. Moissanite is its own gemstone with its own chemistry, and it should always be sold as moissanite, never as a diamond. We explain real, fake and simulant in is moissanite a real diamond? It looks similar to diamond at a glance, but a trained eye or the right tester can tell them apart. Our guide on how to tell moissanite from diamond explains the differences, and our moissanite vs diamond comparison covers price, look and durability side by side.
Moissanite is also different from cubic zirconia (CZ). CZ is much softer (about 8 to 8.5 on the Mohs scale), scratches and clouds more easily, and does not have the same brilliance. See moissanite vs cubic zirconia.
Moissanite colors and grades
Early moissanite from the late 1990s often had a yellow or green tint. Modern colorless moissanite is far whiter and is usually described with diamond-style color letters such as D, E or F. Large stones can still show a faint warm or grey tint in some lights. Clarity is usually very high because the crystals are grown in a lab, and most stones are sold as VVS clarity.
Keep in mind that moissanite grades are given by the seller or by a moissanite card issuer, not by an independent diamond lab. Judge the stone by how it looks and by the seller's return policy, not only by the letters on a card.
Does moissanite last?
Yes. Moissanite is very hard and tough, and it does not fade or change color in normal wear. Like any gemstone, it can look dull when lotion, soap and skin oils build up on the back of the stone. A simple clean with warm water, mild soap and a soft brush brings the sparkle back. Read does moissanite get cloudy? and our moissanite care guide, and see can you wear moissanite every day?
Moissanite vs lab grown diamond
A lab grown diamond is a real diamond, made of carbon, grown in a lab. Moissanite is a different gemstone. Lab grown diamonds cost more than moissanite but are harder and show a white sparkle rather than rainbow fire. Neither one is "better" for everyone; it depends on your budget and the look you want. Our honest comparison, moissanite vs lab grown diamonds, walks through the choice.
Is moissanite worth it?
For many couples, yes: you get a large, bright stone that will last, for much less than a diamond of the same size. It is not the right choice if you want resale value or if you dislike rainbow sparkle. We cover both sides in is moissanite worth it?
Shop moissanite
- Moissanite engagement rings
- Moissanite wedding bands
- Moissanite earrings
- Loose moissanite stones
- Colored moissanite engagement rings
Every piece is made to order in 925 sterling silver or solid gold, and we can also make custom designs.
Quick answers
What is moissanite made of?
Silicon carbide, a compound of silicon and carbon.
Is moissanite natural or lab-made?
Natural moissanite exists but is far too rare and tiny for jewelry. All moissanite gemstones are lab-created.
Is moissanite harder than diamond?
No. Diamond is 10 on the Mohs scale and moissanite is 9.25, which still makes it harder than every other popular gemstone.
Does moissanite sparkle more than diamond?
It shows more colored fire because its dispersion is more than twice diamond's. Some people love the rainbow flashes; others prefer diamond's whiter sparkle.
Does moissanite get cloudy?
No. If it looks dull, it needs cleaning; the stone itself does not cloud over time.