Moissanite vs Diamond: How They Compare

Moissanite and diamond look alike at a glance: both are clear, hard and bright. Up close they behave differently, and the differences decide which one suits you. Here is how they compare on sparkle, durability, size, price and origin.

What moissanite is

Moissanite is silicon carbide. The French chemist Henri Moissan first found it in 1893 in a meteorite crater, where it occurs in tiny amounts. Natural moissanite is far too rare to set in jewelry, so the moissanite in engagement rings today is created in a lab. It is a gemstone in its own right with its own physical properties, distinct from both diamond and cubic zirconia.

Brilliance and fire

Brilliance is the white light a stone returns, and it depends on the refractive index: how strongly the stone bends light. Fire is the flashes of rainbow color you see when a stone moves, measured by dispersion. On both counts moissanite comes out ahead.

In practice, moissanite throws more colorful sparkle than a diamond of the same size. Many people love that extra fire. Others prefer the cooler, whiter sparkle of a diamond. It is a matter of taste, and it is most visible in bright sunlight and in larger stones.

Hardness and durability

Moissanite scores 9.25 on the Mohs scale, second only to diamond at 10. It resists scratching and keeps its polish, which makes it suitable for a ring you wear every day. Cubic zirconia, at 8 to 8.5, scratches more easily and tends to look cloudy over time. Like any gemstone, moissanite can still chip if it takes a hard knock at a corner or point, so take your ring off for sports and heavy work.

Color and clarity

Because moissanite is made under controlled conditions, it can be produced near-colorless and very clean, without hunting through grades the way you would with a natural stone. Every Carissie moissanite comes with a certificate of authenticity that records its color and clarity grades, cut grade and carat weight equivalent.

Carat weight and size

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 usually described by its diamond equivalent weight: the carat weight a diamond of the same dimensions would have. When you compare stones, compare their size in millimeters or their diamond equivalent weight, never moissanite carats against diamond carats.

Price

This is the biggest difference. A moissanite costs a small fraction of a diamond of the same size, so the same budget buys a larger stone, a more detailed setting or both. Many couples put the difference toward the wedding, a honeymoon or a home.

Origin

Lab-created moissanite involves no mining, so there is no question of where the stone came from. If a clear origin matters to you, moissanite answers it simply.

Can people tell the difference?

Most people cannot tell at a normal viewing distance. A trained eye may notice two things up close: the stronger rainbow fire, and, because moissanite is doubly refractive, a slight doubling of the facet edges when the stone is viewed from certain angles through a loupe. Neither changes how beautiful the ring looks on the hand.

Which is right for you?

Choose moissanite if you want maximum sparkle, everyday durability and a larger stone for your budget. Choose a diamond if the tradition of a diamond specifically matters to you or the person you are proposing to. If you are unsure, talk about it together. It is a decision about what the ring means to you both.

Ready to look? Start with our moissanite engagement rings, read more about the stone in Why Moissanite, or compare the nine engagement ring shapes.