Moissanite vs Diamond: The Honest Comparison

The Short Answer

Diamond and moissanite are two different gemstones. Diamond is pure crystallised carbon. Moissanite is silicon carbide, a naturally occurring mineral so rare that nearly all moissanite sold today is lab-created rather than mined. Both are real, durable stones. The choice comes down to price, sparkle style, and what the ring is meant to say.

Hardness and Everyday Durability

Diamond is the hardest known natural material, rated 10 on the Mohs scale of hardness. Moissanite rates 9.25, according to Charles & Colvard, the original patent holder for lab-created moissanite, still hard enough to resist scratching from nearly everything you touch in daily life, including sand, most countertops, and other jewellery except diamond itself.

In practice, both stones hold up to daily wear in a ring worn every day for decades. The gap between 9.25 and 10 shows up in extreme, unusual circumstances, not in normal use.

Sparkle: Fire Versus Brilliance

Diamond and moissanite scatter light differently, and it is the main visual difference a trained eye can spot. Diamond has a refractive index of 2.42, producing what jewellers call brilliance: bright white flashes. Moissanite has a higher refractive index, around 2.65 to 2.69, and produces more fire, meaning more flashes of spectral colour (red, blue, green) as the stone moves under light.

Some buyers want that extra rainbow flash. Others find it too colourful for a classic diamond look, particularly in larger stones or bright sunlight. Viewing both stones in person, side by side, under the same light is the only reliable way to know which look you prefer. Book a consultation at our Coquitlam studio and we will show you both.

Price

Moissanite costs a fraction of a diamond of comparable size. A one-carat, colourless, well-cut moissanite typically runs several hundred dollars, while a one-carat natural diamond of comparable colour and clarity typically runs several thousand. Lab-grown diamonds sit between the two, priced below natural diamonds but still well above moissanite. The exact gap moves with market prices and stone quality, so get a current quote for the specific stone you are comparing rather than relying on a rule of thumb.

Can You Tell Them Apart?

In a top colour grade, a well-cut moissanite can look convincingly like a diamond to a casual observer. A gemologist with a loupe can usually tell the two apart by the extra fire and, in some cuts, slight doubling of facet lines caused by moissanite's double refraction, a property diamond does not have. The Gemological Institute of America (GIA) classifies moissanite as a diamond simulant for exactly this reason: it looks similar but is a chemically distinct mineral.

Does moissanite pass a diamond tester?

It depends on the tester. Basic thermal diamond testers work by measuring how fast a stone conducts heat away from a probe, and moissanite conducts heat quickly enough to register as diamond on many older, thermal-only testers. Dual testers that also check electrical conductivity catch the difference immediately: diamond conducts electricity, moissanite does not. A jeweller using a modern dual tester, or lab equipment, will identify moissanite correctly every time.

Resale and Long-Term Value

Natural diamonds hold resale value better than moissanite, though all gemstones typically resell below their retail price. Moissanite has little to no secondary market value; it is priced for what it is, an affordable, durable stone bought for its own qualities rather than as a store of value. If long-term resale matters to your decision, natural diamond is the stronger choice; if it does not, moissanite's low price is the advantage, not a drawback.

Origin and Ethics

Nearly all moissanite sold today is lab-created, so it carries no mining footprint. Natural diamonds sold internationally are subject to the Kimberley Process Certification Scheme, which tracks rough diamonds to prevent conflict-diamond trade, though the scheme has known limits in scope. Lab-grown diamonds, like moissanite, are not mined. If mining impact is a deciding factor, both moissanite and lab-grown diamond avoid it; natural diamond does not.

Side by Side

Frequently Asked Questions

Sources & Further Reading

• GIA: Simulants, Moissanite and Lab-Grown Diamonds
• Charles & Colvard: Is Moissanite Harder Than a Diamond?
• Kimberley Process Certification Scheme