More fire than a diamond, almost as hard, a fraction of the price. Here is what moissanite is, how it compares to diamond and cubic zirconia, and how to choose the right stone.
What is moissanite?
Moissanite is silicon carbide, a gemstone in its own right. The French chemist Henri Moissan first identified it in 1893 in fragments of a meteorite that fell in Arizona. Natural moissanite is so rare that every moissanite sold today is grown in a lab. That means no mining, a consistent quality and a far lower price than diamond.
Moissanite vs diamond vs cubic zirconia
| Moissanite | Diamond | Cubic zirconia | |
|---|---|---|---|
| Hardness (Mohs) | 9.25 | 10 | 8 to 8.5 |
| Refractive index (brilliance) | 2.65 to 2.69 | 2.42 | 2.15 to 2.18 |
| Dispersion (fire) | 0.104 | 0.044 | 0.060 |
| Everyday wear | Stays bright for life | Stays bright for life | Scratches and clouds over time |
| Price for a 1ct look | Tens of dollars | Thousands of dollars | A few dollars |
In plain words: moissanite reflects more light than diamond and splits it into more rainbow flashes. It is the second-hardest gem used in jewelry, so it resists scratches and keeps its polish. Cubic zirconia looks similar on day one, but it is softer and loses its shine with wear.
Does moissanite pass a diamond tester?
Yes, on most standard testers. The common pen testers measure how fast a stone conducts heat, and moissanite conducts heat much like diamond, so it reads as diamond. Professional multi-testers that also measure electrical conductivity can tell the two apart. A jeweler with a loupe can too, because moissanite shows doubled facet lines when you look through it at an angle.
Color and clarity: what D color, VVS1 means
D color is the top of the color scale: completely colorless, with no yellow or gray tint, even next to a white sheet of paper. VVS1 (very, very slightly included) means any tiny inclusions are practically impossible to see, even under 10x magnification. Our white moissanite is D color, VVS1 throughout.
Colored moissanite (pink, green, blue, red, black, yellow) is grown with its color. It has the same hardness and fire as the white stones.
Carat weight and size
Moissanite is about 10% lighter than diamond, so a 6.5mm moissanite does not weigh exactly 1 carat. Jewelers use DEW (diamond equivalent weight): the weight a diamond of the same size would have. When we say 1ct, we mean a stone that looks like a 1ct diamond. Here is the size chart for round stones:
| Diameter | Carat (DEW) | How it reads |
|---|---|---|
| 3mm | 0.1ct | A pinpoint of light, perfect for a second piercing |
| 4mm | 0.3ct | Dainty, everyday |
| 5mm | 0.5ct | Noticeable but quiet |
| 6.5mm | 1ct | The classic size for studs and solitaires |
| 8mm | 2ct | Clearly a statement |
| 9mm | 3ct | Bold, seen across the room |
| 11mm | 5ct | Red-carpet scale |
Which cut should you choose?
- Round brilliant: the most fire and the most classic look. The safe bet for studs, solitaires and tennis bracelets.
- Oval and pear: longer shapes that make fingers and earlobes look finer.
- Emerald and asscher: step cuts with wide, calm flashes of light. Art deco and minimal.
- Princess and radiant: square and rectangular shapes with lots of sparkle.
- Heart and marquise: romantic, a little unexpected.
Is moissanite a good choice for an engagement ring?
Many couples choose it for exactly that. It is hard enough for daily wear, stays brilliant for life and frees up budget for a bigger stone or the honeymoon. Browse our moissanite engagement rings and matching wedding bands.
How to care for moissanite
The stone itself needs very little: warm water, a drop of mild soap and a soft toothbrush bring back full sparkle. The metal needs more attention, especially plating. See our jewelry care guide.
Ready to see it on? Start with our best sellers or the solitaire studs, the easiest first piece.