What Is Moissanite? Origins, Properties and How It Compares

Moissanite is a luminous gemstone made of silicon carbide (SiC), first identified in 1893 by the French chemist Henri Moissan in crystals from a meteorite crater in Arizona. It is not a diamond and not an imitation of one; it is a gemstone in its own right, with a refractive index and fire that exceed diamond's and a hardness second only to it. Because natural crystals are microscopic, every moissanite in jewelry today is grown in a laboratory. This guide explains what moissanite is, where it came from, how it performs, and what to know before you buy.

What Moissanite Actually Is

A distinct mineral, not a diamond substitute.

Moissanite is the gem name for crystalline silicon carbide. In a diamond, every atom is carbon; in moissanite, silicon and carbon atoms bond in an entirely different structure. That difference changes how the stone forms, how it bends light, how it is graded, and what it costs. The result is a colorless gem that returns more white light and more rainbow fire than diamond, while sitting just below it in hardness.

Because of its brilliance, moissanite has become one of the most popular non-diamond center stones for engagement rings. The Gemological Institute of America, in its original 1997 study of the gem, noted that with its refractive index, dispersion, and hardness, moissanite is far closer to diamond in appearance and heft than any earlier colorless stone. It stands apart, though, on its own merits, and understanding those is the point of this guide.

The Meteorite Origin Story

Born among the stars, named for the man who found it.

Natural moissanite: stardust

Natural moissanite is extraordinarily rare on Earth. It occurs in minute grains in meteorites, in kimberlite pipes (the same volcanic formations that carry diamonds to the surface), and in a few deep ultramafic rocks. Silicon carbide grains recovered from meteorites carry isotopic signatures showing they formed around carbon-rich stars beyond our solar system, long before the sun existed. The largest natural crystals ever found measure only a few millimeters, per GIA's Gems & Gemology; nothing in nature is big enough to cut.

Henri Moissan and Meteor Crater

In 1893 Henri Moissan examined rock from Meteor Crater near Canyon Diablo, Arizona, and found tiny glittering crystals he at first believed were diamonds. In 1904 he identified them as silicon carbide, a compound so rare on Earth that the discovery felt like a message from another world. The mineral was named moissanite in his honor; Moissan went on to win the Nobel Prize in Chemistry in 1906.

How Lab-Grown Moissanite Is Made

Recreating stellar conditions without the billion-year wait.

Gem-quality moissanite is grown by a thermal process that bonds silicon and carbon under extreme heat into a single crystal boule, which is then cut and polished like any fine gem. The first gem-grade stones reached the jewelry market in 1998, and the original patents expired worldwide by 2018, opening the field to multiple growers and making moissanite more accessible than ever. A crystal takes weeks to months to grow and yields near-flawless material with exceptional optical properties. Wondering how that differs from growing a diamond? See is moissanite a lab-grown diamond?

Moissanite Properties: Brilliance, Fire, and Hardness

Why it performs so differently from other stones.

Brilliance and refractive index

Brilliance is how much light a stone returns to your eye, and the measure behind it is refractive index (RI). Moissanite's RI is 2.65–2.69; diamond's is 2.42. More light enters, bounces inside, and comes back brighter, which is why moissanite reads so vivid in daylight and under lamps. Moissanite is also doubly refractive: light splits into two rays as it passes through. Under magnification you may see a faint doubling of the back facets, but stones are cut along the optic axis to minimize it, and to the naked eye you simply see intense sparkle.

Fire and dispersion

Fire is white light split into its rainbow. Moissanite's dispersion is 0.104 against diamond's 0.044, roughly 2.4 times the colored flash. Under sunlight, spotlights, or candles it throws greens, blues, oranges, and violets across its facets. Some buyers love the drama; others prefer diamond's more balanced white sparkle. Neither preference is wrong.

Hardness and durability

Moissanite scores 9.25 on the Mohs scale, second only to diamond at 10 and above sapphire and ruby at 9. It resists scratching in daily wear, resists chipping because it has no cleavage planes, and does not cloud or lose sparkle over time. It is also heat-resistant, so a ring can be resized, soldered, and steam-cleaned without risk to the stone.

For the CZ comparison in depth, read moissanite vs cubic zirconia.

Is Moissanite a Diamond?

No — and it is not trying to be.

Moissanite is not a diamond, a type of diamond, a synthetic diamond, or a fake diamond. It is an entirely different gemstone with its own chemistry (silicon carbide versus pure carbon), its own optics, and its own identity. Both sparkle, both are used in engagement rings, and both are exceptionally hard, but moissanite exceeds diamond in brilliance, fire, and heat resistance while sitting slightly below it in hardness. For the full head-to-head, see moissanite vs diamond.

Quick Comparison: Moissanite vs Diamond

How the two stack up in one glance.

Hold a moissanite next to a diamond in direct sunlight and the moissanite throws more vivid rainbow flashes, while the diamond gives a more balanced white sparkle. Both are beautiful, both are durable; they are simply different gemstones. If you are deciding between moissanite and a grown diamond specifically, our moissanite vs lab-grown diamond guide covers it.

Moissanite Color Grades Explained

Graded on the same D-to-Z letter scale as diamond.

Moissanite is graded on a color scale modeled on the GIA diamond color system, from completely colorless to faint warm tints. Choosing the right grade for your metal is one of the most important decisions when buying, because moissanite can shift slightly with lighting and may not always read perfectly colorless in every setting.

A colorless grade keeps a stone crisp against cool white gold or platinum. Near-colorless grades look seamless in yellow gold and rose gold, where the metal's warmth complements the stone. Gray moissanite brings a stormy, celestial look for buyers who want something beyond white. The letter scale itself is explained in our 4Cs of diamonds guide.

Popular Shapes and Settings

Every cut brings out a different side of the stone.

• Round brilliant — maximum fire and sparkle; the most popular engagement cut.
• Oval — elongates the finger with a modern edge.
• Cushion — soft, romantic corners for antique-inspired settings.
• Emerald — sleek step-cut elegance; choose a colorless grade since open facets show tint.
• Marquise — dramatic and lengthening.
• Pear and princess — distinctive silhouettes with brilliant-cut sparkle.

Moissanite works in every setting: solitaires let its brilliance take center stage, halos and hidden halos amplify sparkle, vintage designs pair it with milgrain and filigree, and nature-inspired and fantasy-inspired settings connect its cosmic origin to organic beauty. Our styles and setting types guide walks through each.

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Moissanite Engagement Rings

Colorless and gray moissanite in every cut, handcrafted and made to order in silver, vermeil, or solid gold.

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Why Choose Moissanite?

Beauty, price, and a clean origin.

Affordability without compromise

A colorless moissanite runs roughly $300–$800 per carat, against about $3,000–$15,000 or more per carat for a mined diamond, and its price does not spike with carat weight the way diamond's does. The same budget therefore buys a noticeably larger stone, a solid gold setting, or savings kept in your pocket.

Ethics and sustainability

All moissanite is lab-grown, so there is no mining, no land displacement, and no conflict supply chain. It is mining-free by nature, and independent labs such as IGI now issue standardized grading reports for moissanite, a sign of a maturing category. Every moissanite we set is lab-created and traceable.

Honest Limitations

What to know before you buy.

• Resale value. Moissanite holds little resale value. Buy it because you love it, not as an investment.
• Perception. Some family circles still equate value with natural diamond. Be ready for that conversation if it matters to you.
• Fire intensity. The vivid rainbow flash is a preference; if you want understated white sparkle, a diamond may suit you better.
• Certification. GIA does not grade moissanite; reports come from labs such as IGI and GRA. If GIA paperwork matters, a diamond is the only route.
• Testers. Moissanite passes a thermal diamond tester; only an electrical tester separates them. See does moissanite pass a diamond tester?

How to Care for Moissanite Jewelry

One of the lowest-maintenance gems you can own.

1. Clean at home with warm water, mild dish soap, and a soft toothbrush to lift oils and buildup.
2. Ultrasonic and steam cleaners are safe for moissanite; use them freely at home or at your jeweler.
3. Remove it before lotions, perfume, and hairspray, which leave a film that dulls sparkle between cleanings.
4. Store it separately so it cannot scratch softer stones such as opal or pearl.
5. Take it off for heavy manual work and gym sessions to protect the setting, not the stone.
6. Have the prongs checked yearly; our jewelry cleaning guide covers the full routine.

If a moissanite ever looks hazy, the stone is not degrading; it is surface residue. A five-minute soak and a gentle scrub restore it completely.

Moissanite FAQ