Moissanite vs Cubic Zirconia (CZ): Which Is the Better Diamond Alternative?

Moissanite is the better stone. It's harder (9.25 on the Mohs scale against 8 to 8.5 for cubic zirconia), brighter, has more fire, and passes a standard diamond tester. Cubic zirconia (CZ) costs a fraction of the price and looks similar at first glance, so it's a fair choice for a piece you'll wear now and then, or when budget comes first.

We sell both, so we won't pretend CZ is junk. Below we compare the two using GIA's figures, show what each costs in our range, and explain how to tell them apart, including which of our two lines a product is from.

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Moissanite vs cubic zirconia at a glance

These are the standard gemological figures for each stone, with diamond alongside for reference:

For most buyers, two things decide it: hardness, which sets how a stone looks after years of wear, and the tester results, if you want a piece that tests as diamond.

Those are the listing photos for the two chains, with prices as of October 13, 2026. In photos they look much alike. The differences show up in the specs, on a tester, under a loupe and after years of wear.

What is moissanite?

Moissanite is the gem form of silicon carbide, a compound of silicon and carbon. The French chemist Henri Moissan first found it in 1893, in a meteorite crater in Arizona. Natural moissanite only turns up as tiny grains, so all moissanite used in jewelry is grown in a lab. Colorless moissanite became popular as a diamond imitation in the late 1990s.

It's the hardest of the diamond look-alikes, at 9.25 on the Mohs scale, second only to diamond. GIA describes it as having slightly more brilliance than diamond and more than twice the fire. For the full background, read is moissanite a real diamond?

What is cubic zirconia?

Cubic zirconia is a lab-made crystal of zirconium dioxide, with a little yttrium oxide or calcium oxide added to keep its cubic structure stable. A natural form was identified in 1937, but only as tiny crystals inside another mineral, so all the CZ in jewelry is man-made.

The breakthrough was skull melting, a method developed in the USSR in 1972. Pure zirconia melts at about 2,750°C, too hot for an ordinary crucible, so the melt is held inside a crust of its own powder and then cooled slowly while large crystals grow. CZ went on sale as a diamond imitation in 1976 and soon became the most common one. By the end of 1980, makers were producing about 60 million carats a year.

That volume keeps CZ cheap: GIA puts it at often less than 5% of the price of a comparable diamond. It's the stone in our lower-priced line, and our guide to cubic zirconia covers it in more depth.

Moissanite vs CZ: the key differences

Sparkle and fire

Brilliance, the white light a stone sends back to your eye, follows refractive index. Moissanite's is the highest of the three (2.65 to 2.69), diamond's is 2.42 and CZ's is 2.15 to 2.18. So moissanite looks brighter than CZ, and CZ is less bright than diamond.

Fire, the rainbow flashes, follows dispersion: about 0.104 for moissanite, 0.058 to 0.066 for CZ and 0.044 for diamond. CZ has slightly more fire than diamond but less brilliance, and GIA notes that some people find its broad flashes of color look artificial. From a few feet away, both look bright on a chain. Up close and in sunlight, moissanite is livelier.

Durability

This is the difference that matters most for daily wear. GIA rates CZ as durable enough to wear every day, but more prone to scratches and abrasion over time. In practice, the sharp edges where facets meet slowly soften, the surface picks up fine scratches, and the stone looks duller. Cleaning won't fix scratches. CZ is also somewhat brittle, so a hard knock can chip it.

Moissanite, at 9.25, resists that wear far better and keeps its sharp look much longer. Color is the other long-term difference. GIA notes that colorless CZ may yellow over time. Moissanite doesn't cloud or change color with age.

Weight

CZ is much denser. Its specific gravity is 5.6 to 6.0, against about 3.22 for moissanite, so a CZ weighs about 1.7 to 1.9 times as much as a moissanite of the same size. That's why carat numbers can mislead: CZ may be sold by size, by actual weight or by "diamond-equivalent" weight, and listings don't always say which. Moissanite is often described by diamond-equivalent weight too, including on our chains. Compare stones by millimeter size instead.

Moissanite vs CZ price

Here's the gap in our own range, as of October 13, 2026:

For similar chains, moissanite costs about 3 to 4.5 times as much as CZ in our range. CZ has been made in huge volumes since the late 1970s, which keeps it cheap. With our moissanite you're also paying for D color VVS1 stones that come with a GRA report.

Does CZ pass a diamond tester?

No. A standard diamond tester measures how fast heat moves through the stone. Diamond conducts heat better than any other gem. Moissanite comes close enough that heat-based testers read it as diamond, as GIA reported in 1997. CZ conducts heat poorly, and GIA notes it is easily separated from diamond on thermal conductivity. So CZ fails.

A multi-tester adds an electrical conductivity check. Moissanite conducts a little electricity and diamond almost never does, so a multi-tester flags moissanite. CZ fails the heat check before the electrical one matters. Our post on whether moissanite passes a diamond tester explains how the testers work.

Every piece in our moissanite line passes a standard diamond tester. Pieces in our CZ line won't.

How to tell CZ from moissanite

At arm's length, most people can't. These checks work:

1. Use a diamond tester. CZ fails a heat-based tester and moissanite passes. It takes seconds.
2. Breathe on it. Fog clears from moissanite almost at once and lingers longer on CZ. It's a rough version of the heat test, so compare it with a stone you know.
3. Look through a 10x loupe. Moissanite is doubly refractive, so its back facet edges look doubled when you look in at a slight angle. CZ is singly refractive and shows no doubling. Worn CZ also shows scratched, rounded facet edges.
4. Weigh a loose stone. At the same size, a CZ is about 1.7 to 1.9 times heavier.
5. Check the paperwork. Our moissanite ships with a GRA report you can check. A GRA report describes moissanite, so a CZ shouldn't come with one.

For other diamond look-alikes, such as glass and white sapphire, see our simulated diamond vs moissanite comparison.

Which is better, moissanite or cubic zirconia?

For a chain or bracelet you'll wear often, moissanite. But three questions decide it for you.

What's your budget?

If you want a tennis chain 4.5mm or wider for $100 to $300, that's CZ: our 4.5mm CZ chain starts at $99.99, and our 5mm moissanite chain at $449.99. In moissanite, that money buys a finer piece, such as our 1.5mm Moissanite Micro Tennis Chain at $254.99 to $269.99, or our 3mm Moissanite Tennis Bracelet at $184.99 to $199.99 (prices as of October 13, 2026).

How often will you wear it?

Daily wear is where CZ falls behind. It will scratch and dull sooner, so a CZ chain worn every day won't look new for as long. For weekends, events, or trying a style before spending more, CZ is fine.

How much sparkle do you want, and should it test as diamond?

Moissanite is brighter and has more fire. If strong rainbow flashes in big stones aren't for you, look at both in person first. And if the piece needs to pass a diamond tester, only moissanite will.

CZ is a good fit if you want the iced look on a tight budget, you'll wear it now and then, or you're trying a size or style. Moissanite is a good fit if you'll wear it daily, you want it to keep its look for years, or you want a stone that tests as diamond and comes with a grading report.

We sell both: how to tell which line you're buying

• Moissanite line: D color VVS1 moissanite, a GRA report with every piece, and it passes a standard diamond tester. On our silver-finish chains, the Material line reads 18K white gold plating.
• CZ & Metal Alloy line: cubic zirconia on gold-plated metal alloy, at a fraction of the price. It won't pass a diamond tester.

To check a product, read the title first. Our moissanite pieces say Moissanite in the name, with the grade, such as "5mm Moissanite Tennis Chain - Silver - D Color - VVS1". Then read the specs. On a moissanite piece, the Stone Type line names moissanite and says GRA Report Included. On a CZ piece, the Stones line lists diamond simulants and the Gold line says Plated. In our range, those simulants are cubic zirconia. If a title doesn't say Moissanite, check the Stones line before you buy.

Returns differ too. In-stock pieces from the CZ & Metal Alloy line can be returned unworn within 14 days for a refund, less a 15% restocking fee, or within 90 days for an exchange or store credit. Moissanite pieces are final sale, so check your size first. Both lines come with our lifetime warranty card, which covers manufacturing defects, breakage in normal wear, fading or tarnishing of the finish, and loose or lost stones. The details are in our refund policy.

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Moissanite vs cubic zirconia: common questions

Is moissanite better than cubic zirconia?
For most buyers, yes. It's harder (9.25 vs 8 to 8.5 on the Mohs scale), brighter, has more fire and passes a standard diamond tester. CZ's advantage is price.

Are moissanite and cubic zirconia the same thing?
No. Moissanite is silicon carbide and CZ is zirconium dioxide. They're different materials that both imitate diamond, and both are made in labs.

Does cubic zirconia pass a diamond tester?
No. CZ conducts heat poorly, so a standard heat-based diamond tester shows it isn't a diamond. Moissanite passes that test.

Can you tell the difference between CZ and moissanite?
Not easily by eye. A diamond tester settles it in seconds: CZ fails, moissanite passes. Under a 10x loupe, moissanite shows doubled facet edges and CZ doesn't, and a loose CZ is about 1.7 to 1.9 times heavier than a moissanite of the same size.

Why is moissanite more expensive than cubic zirconia?
CZ has been mass-produced since the late 1970s and is cheap to make. Moissanite is the harder, brighter stone, and ours is graded with a GRA report. For similar chains in our range, moissanite costs about 3 to 4.5 times as much as CZ.

Does cubic zirconia get cloudy?
Not inside, but it can look cloudy. CZ picks up fingerprints and smudges easily, fine scratches dull it over time, and colorless CZ may yellow. Cleaning removes film, but not scratches.