Moissanite vs Cubic Zirconia: Differences, Price and How to Tell Them Apart

Moissanite and cubic zirconia (CZ) are both lab-made stones that look like diamond, but they are very different in hardness, sparkle, weight, price and how they age. In short: CZ is an inexpensive look-alike that scratches and dulls over the years; moissanite is a hard, long-lasting gem that keeps its sparkle for life and costs more. Here is the full comparison, and how to tell the two apart.

At a Glance

Where They Come From

Moissanite was first found by Henri Moissan in 1893 as tiny crystals from Meteor Crater in Arizona. Natural moissanite is far too rare for jewelry, so every moissanite gem is grown in a lab; gem-quality stones reached the market in 1998. Read what is moissanite?

Cubic zirconia also exists in nature only as microscopic grains. The gem material is made by melting zirconium oxide with a stabilizer at very high temperature, a method developed in the 1970s that made CZ cheap and plentiful. It became the best-known diamond imitation of the late twentieth century.

Durability: The Biggest Difference

Everyday dust contains quartz, which is about 7 on the Mohs scale. At 8 to 8.5, CZ is harder than quartz, but only just, so years of daily wear slowly scratch its surface and round its facet edges. A worn CZ looks soft and slightly milky. Moissanite, at 9.25, is second only to diamond among jewelry gems and keeps sharp facets and a high polish for decades. That is why moissanite suits an engagement ring worn every day, and CZ suits fashion jewelry or a placeholder ring. More in will moissanite last forever?

Sparkle

Moissanite's refractive index is far higher than CZ's, so it returns more light and looks brighter. Its dispersion is also higher, so it shows more rainbow fire. A new CZ can look lively, but its sparkle is softer and glassier, and it fades as the surface wears. Read why moissanite sparkles so much.

Price

CZ costs very little because it is quick and cheap to make in large crystals. Moissanite crystals take far longer to grow and cut, so moissanite costs more, though still a small fraction of diamond. See our moissanite ring price guide. Neither stone is an investment: both resell for far less than the purchase price.

How to Tell Moissanite from Cubic Zirconia

• Weight. CZ is much denser. A loose CZ weighs roughly 1.7 times as much as a moissanite of the same size, which a jeweler can check on a scale.
• Diamond tester. A basic thermal tester reads moissanite as diamond but CZ as "not diamond", because CZ carries heat poorly.
• Loupe. Under 10x magnification, moissanite often shows doubled facet edges when you look through the stone at an angle. CZ is singly refractive, so its facet edges look single.
• Wear. On a stone that has been worn for a while, scratches and rounded facet edges point to CZ.
• Fog. Breathe on the stone. Fog usually lingers a little longer on CZ, while it clears almost instantly from moissanite and diamond. Treat this as a hint, not proof.

For telling moissanite from diamond as well, see how to tell moissanite from diamond and does moissanite pass a diamond tester?

Which Should You Choose?

• Choose moissanite for an engagement ring, wedding band or any piece you want to wear every day for years.
• Choose CZ for fashion jewelry, a travel ring or a temporary placeholder, where low cost matters more than longevity.
• Want a real diamond? A lab grown diamond is the diamond option; compare it in moissanite vs lab grown diamond and best diamond alternatives.

Quick Answers

Is moissanite better than cubic zirconia?

For jewelry worn every day, yes: it is harder, more brilliant and keeps its look for life. CZ is cheaper and fine for occasional wear.

Does cubic zirconia get cloudy?

Over years of wear its surface scratches and its edges round, which makes it look cloudy. Moissanite does not; see does moissanite get cloudy?

Is moissanite just expensive CZ?

No. They are different materials: moissanite is silicon carbide, CZ is zirconium dioxide, and they differ in hardness, sparkle and weight.

Can a jeweler tell moissanite from CZ?

Easily, with a tester, a loupe or a scale.

Browse our moissanite engagement rings.