What is moissanite?
By Jared James · Last updated 27 October 2026
Quick answer
Moissanite is a lab-grown gemstone made of silicon carbide. It is 9.25 on the Mohs scale, just below diamond at 10, and shows more rainbow fire than diamond. With us, a 6.5mm round moissanite, about the size of a 1 carat diamond, costs $650, about half the price of a typical 1 carat lab-grown diamond.
What is moissanite?
A lab-grown gemstone made of silicon carbide, harder than everything except diamond, with more rainbow fire. The French scientist Henri Moissan identified the mineral in 1893 in fragments from a meteorite crater in Arizona. Natural moissanite is too rare for jewellery, so the moissanite in rings is grown in a lab, then cut and polished the same way as diamond.
Is moissanite a real diamond?
No. Moissanite is silicon carbide and diamond is carbon, so they are different minerals. According to GIA, thermal diamond testers react to moissanite as if it were diamond, but the two are easy to separate under magnification, where moissanite’s facet edges look doubled. A lab-grown diamond, by contrast, is real diamond: the same carbon crystal as a mined one.
How does moissanite compare with diamond and lab-grown diamond?
Moissanite has more fire and costs less; diamond, lab-grown or mined, is harder and has a whiter, calmer sparkle. Lab-grown and mined diamond share every figure in the table below except price. The moissanite figures are from GIA’s study of synthetic moissanite, and the longer comparison is in moissanite vs diamond.
| Property | Moissanite | Lab-grown diamond | Mined diamond |
|---|---|---|---|
| Material | Silicon carbide | Carbon | Carbon |
| Hardness (Mohs) | 9.25 | 10 | 10 |
| Refractive index | 2.65 to 2.69 | 2.42 | 2.42 |
| Fire (dispersion) | 0.104 | 0.044 | 0.044 |
| Under magnification | Facet edges look doubled | Single, sharp facet edges | Single, sharp facet edges |
| About 1 carat in size, with us | $650 for a 6.5mm round | $1,321 for a typical 1 carat IGI stone | Sourced on request |
How much does moissanite cost in Australia?
With us, a 6.5mm round moissanite, about the size of a 1 carat diamond, costs $650, and a complete Hailey solitaire with one costs $1,910 in 14k gold or $2,210 in 18k gold. At 1 and 2 carat sizes, moissanite costs about half as much as a lab-grown diamond with us.
| Stone | Moissanite | Typical IGI lab-grown diamond |
|---|---|---|
| 6.5mm round, about 1 carat | $650 | $1,321 |
| 8mm round, about 2 carats | $1,390 | $2,600 |
| Hailey solitaire in 18k gold, 1 carat look | $2,210 ($1,910 in 14k gold) | $3,200 |
Moissanite prices are from our ring builder. Lab-grown prices are the typical (median) IGI-graded stone on our builder at 1 and 2 carats, any shape, D to F colour and VS1 clarity or better. The Hailey prices are a 6.5mm moissanite on a 1.8mm band and our complete 1 carat lab-grown Hailey on a 2mm band. Checked 27 October 2026.
Round moissanite runs from 6.5mm to 11mm ($3,110). Ovals run from 7x5mm ($550) to 11x9mm ($2,360), with an 8x6mm oval at $1,080; see our oval moissanite engagement rings. For complete rings at each size, read what a moissanite engagement ring costs in Australia.
What size moissanite looks like a 1 or 2 carat diamond?
About 6.5mm across for a 1 carat look and 8mm for a 2 carat look, in a round. A well-cut 1 carat round diamond measures about 6.4 to 6.5mm and a 2 carat about 8.1mm.
Moissanite is a little lighter than diamond (a specific gravity of 3.22 against 3.52), so a moissanite of the same size weighs less. That is why we sell moissanite by millimetres rather than carats, and why you will see "diamond equivalent weight" elsewhere: the carat weight of a diamond with the same measurements. Compare stones in millimetres.
Will people think moissanite looks fake?
Most people cannot tell at arm’s length. Moissanite’s extra rainbow fire shows most in sunlight and under spotlights, and in stones over about 1 carat. Some people love the colour; others prefer the calmer look of diamond, so watch both stones move on video before you choose. More is in does moissanite look fake?
Is moissanite durable enough to wear every day?
Yes. At 9.25 on the Mohs scale, moissanite is harder than every gemstone except diamond; sapphire and ruby are 9. It handles hand washing, cooking and travel, and it holds up well in the pointed tips of pears and marquises. Clean it with warm soapy water and a soft brush, and have the claws checked once a year. More is in can I wear a moissanite ring every day?
Pear
A pear moissanite held by three prongs, one on its point.
Marquise
A marquise moissanite held by six prongs.
Does moissanite have any resale value?
Very little. Buy moissanite for the look and the budget, not to sell later. Lab-grown diamonds also resell for far less than they cost new; how much is in do lab-grown diamonds hold their value?
What are the downsides of moissanite?
More rainbow fire than some people want, very little resale value, and the occasional question about whether it is a diamond. It is also a little softer than diamond, so it can pick up fine wear over many years. Each one is covered in the downsides of moissanite.
Frequently asked questions
- Is moissanite a diamond?
- No. Moissanite is silicon carbide and diamond is carbon. Both are very hard and both sparkle, but they are different minerals with different optical properties.
- Is moissanite a poor man’s diamond?
- Some people call it that, but moissanite is a gemstone in its own right, chosen for its sparkle and its price. With us, a 6.5mm moissanite costs about half as much as a typical 1 carat lab-grown diamond.
- Is a moissanite worth anything?
- Very little secondhand. Its value is in the ring you wear: a bigger, brighter stone for the budget.
- Will moissanite turn yellow or cloudy?
- No. Moissanite keeps its colour and clarity. Cloudiness is dirt or oil on the surface, and it cleans off with warm soapy water and a soft brush.
- What colour is moissanite?
- Modern moissanite is near colourless and is described with the same D to Z colour letters as diamond. Larger stones can show a faint warm tint in warm indoor light, as large diamonds can.
- Can people tell moissanite from diamond?
- Most people cannot tell by looking. Moissanite has more rainbow fire, and under magnification its facet edges look doubled, which is how a jeweller tells them apart. Thermal diamond testers can read moissanite as diamond.
- How is moissanite made?
- Almost all moissanite is grown in a lab, where silicon and carbon are combined at very high temperatures to form silicon carbide crystals. The crystals are then cut and polished like diamonds.
- Can moissanite be set in a wedding band?
- Yes. We make wedding bands set with moissanite, up to full eternity, and can design one to sit against your engagement ring.
