In 1893 a French chemist named Henri Moissan was picking through rock from Meteor Crater in Arizona and found crystals he took for diamond. He was wrong, and it took him eleven years to work out what they actually were: silicon carbide, a compound of silicon and carbon that had never been found on earth before. The mineral is named after him.
Natural moissanite is vanishingly rare — a few grains in meteorites and a handful of terrestrial deposits. Everything on the market is grown, which is not a secret and not a shame. It is the only honest way to have any.
The three differences that matter
1. It throws more colour
Dispersion is a measure of how much a stone splits white light into the spectrum. Diamond is 0.044. Moissanite is 0.104 — more than twice as much. Jewellers call the effect fire, and in moissanite it is unmistakable: move your hand under a spotlight and you get flashes of orange, green and blue rather than white sparkle.
Some people love this and some people find it too much. It is the single most reliable way to tell the two apart across a table, and it is a matter of taste rather than quality. A diamond is the more restrained stone. A moissanite is the more theatrical one.
2. It is nearly as hard
Mohs 9.25 against diamond's 10. That gap sounds small and is not — the Mohs scale is ordinal, not linear, and diamond is several times harder than the number suggests. But the practical threshold is well below both: anything above about 8 will not be scratched by ordinary wear, because household dust is quartz at 7. Moissanite clears that comfortably. It is harder than sapphire.
3. It is a different mineral
This is the part that gets muddled. A lab-grown diamond is a diamond — same carbon, same lattice, grown in a machine instead of a mantle. Moissanite is not a diamond at all and never was. It is silicon carbide. Calling it a diamond simulant is technically right; calling it a fake diamond is like calling a cello a fake violin.
What it does not do
It does not cloud over. It does not go yellow. Silicon carbide is chemically stable and is not affected by heat, light or the things in a kitchen. The stories about moissanite “turning” come from old cubic zirconia, which is a different material entirely and does degrade.
How to look after it
Washing-up liquid, warm water, a soft toothbrush around the setting. Moissanite is one of the few stones you can safely put in an ultrasonic cleaner. The setting is the vulnerable part, not the stone — check the claws once a year the way you would with any ring.
Where we use it
Four pieces, all in solid 925 sterling silver: an oval in a leaf setting, a marquise on a branch band, a marquise in a floral vine, and a plain solitaire. We put moissanite where the design wants a clear stone that carries light, and we say what it is on every page — never “diamond simulant”, never a hedge.
The moissanite pieces →
New Classics — familiar shapes done properly →
How to measure your own finger at home →
We name every stone and every treatment on the product page. If a page does not say a stone is natural, ask us and we will tell you.