Moissanite vs Diamond: Fire, Durability & Price Compared

Moissanite (silicon carbide) is the most serious diamond simulant on the market, and understanding what it actually is — and isn't — matters more here than for any other diamond alternative.

Simulant, not substitute

Moissanite is lab-created, not mined, and gemologically distinct from diamond in composition — it's correctly described and sold as a diamond simulant, never as any kind of diamond. This is a different category entirely from lab-grown diamond, which is chemically real diamond grown in a lab; moissanite is a genuinely different mineral that happens to resemble diamond closely enough to be mistaken for it by eye.

Durability: nearly diamond, comfortably enough for daily wear

At roughly 9.25-9.5 on the Mohs scale, moissanite sits just below diamond's 10 — a gap that matters for industrial cutting tools but is essentially irrelevant for a ring worn daily. It's genuinely durable enough for everyday wear in any setting, including exposed prongs.

More fire, less pure brilliance

Moissanite has noticeably more fire (the coloured flashes of light a stone throws, as distinct from brilliance, the white light return) than diamond — some buyers love the extra rainbow sparkle, especially in direct sunlight or under spotlighting, and others find it reads as too obviously "sparkly" for a classic, diamond-like look. This is the single biggest reason a knowledgeable observer can sometimes spot moissanite without equipment: not colour or clarity, but an unusually strong flash of coloured fire under bright, direct light.

The definitive test, if it matters to you

Under magnification, moissanite shows double refraction — facet edges appear doubled when viewed through a loupe, a genuine optical property diamond never exhibits. This is the reliable way a gemologist confirms moissanite versus diamond, distinct from the fire-based visual impression alone.

Price: a small fraction of diamond, at any comparable size

Moissanite costs a small fraction of an equivalent-looking diamond, whether natural or lab-grown, at any given size — the single biggest reason buyers choose it, whether for budget reasons or simply to get significantly more visible size for the spend.

Related reading

• Non-diamond engagement rings: sapphire, ruby, emerald & moissanite
• Lab-grown vs natural diamonds: what buyers need to know
• Sapphire vs diamond engagement ring: which to choose

Sources: moissanite properties and fire/brilliance comparison per GIA (gia.edu) and current trade retailer buying guides.