Is Moissanite a Lab Grown Diamond? No — Here's the Difference

Moissanite and lab grown diamonds share product photos, lighting setups and sometimes the same product page section. They do not share a chemistry. One is silicon carbide, the other is carbon, and no amount of grading closes that gap.

The short answer is no

Moissanite is silicon carbide, written SiC. A lab grown diamond is pure carbon, written C, grown from a carbon seed in a reactor or press instead of being mined. The only thing the two genuinely have in common is that people make them. Chemistry, crystal structure, hardness, the way they bend light, and the paperwork that ships with them are all separate. Calling moissanite "a lab grown diamond" is not a loose description — it is the wrong material name.

Silicon carbide versus carbon

A diamond is a cubic lattice of carbon atoms, one element, bonded in three directions. That structure is why it reaches 10 on the Mohs scale and why it refracts light as a single beam. Moissanite is a compound: silicon and carbon in a hexagonal crystal, hardness 9.25. Because its crystal is not optically isotropic, light entering the stone splits into two paths. That property is called birefringence, and it does two visible things. It gives moissanite noticeably more fire — the coloured flashes — than a diamond of the same size. And under magnification, the back facets appear doubled, as if the stone had a faint ghost image behind it.

That doubling is not a defect. It is the physical signature of the material.

Why the two get marketed together

Three pressures push the words into the same sentence. The first is search behaviour: shoppers type "lab grown" because that is the vocabulary they were handed, so listings fold moissanite into that phrase to be found. The second is price anchoring — placing moissanite next to a lab diamond makes the moissanite look like a bargain and the diamond look like the upgrade, and both presentations sell. The third is supplier shorthand. "Lab grown" describes a manufacturing route, not a substance, and loose usage has blurred it into a material claim.

None of that is illegal, and most of it is not deliberately deceptive. It is still confusing. The reliable test is simple: ask what the stone is made of — silicon carbide or carbon.

GRA and IGI are two separate systems

This is where the confusion becomes practical. GRA cards accompany moissanite. IGI grades lab grown diamonds. They are different organisations serving different materials, and neither certifies the other's product. A GRA card records what the supplier states about a moissanite — colour grade, clarity grade, measurements, and a card number you can match to the stone. An IGI report records the four Cs of a diamond plus its growth method and proportions.

So a listing offering "IGI certified moissanite" is describing something that does not exist, and a diamond shipped with a GRA card has the same problem in reverse. Our moissanite is GRA D colour, VVS1. Our lab grown diamonds carry IGI reports. The paperwork tells you which material you are holding before you ever look at the stone.

What it does to price

Moissanite is priced as a manufactured product: cost of production plus a margin. Lab grown diamonds are priced against a moving market, and as growth capacity has expanded, those prices have come down noticeably over the past several years. Mined diamonds sit on a separate ladder again, propped up by scarcity narrative and decades of advertising.

What it does to resale

On resale, be realistic. A moissanite is worth roughly what a used piece of jewellery is worth — the metal and the setting. A lab grown diamond resells far below its retail price, and a mined diamond resells below retail too but with a thicker second-hand market. If resale is your goal, none of these three is an investment. If the goal is a stone you wear for twenty years, resale is irrelevant to the decision.

What this means when you are choosing

If what you want is a diamond — the optics, the 10 hardness, the IGI report, the thing that appraises as a diamond — buy a lab grown diamond and accept its price. If you want maximum size and fire per dollar on a ring you wear daily, moissanite does that better than anything else at its price, and 9.25 hardness is ample. What you should not do is buy moissanite hoping it will be treated as a diamond later, by an insurer, an appraiser or a buyer. It will not be, and the certificate in the box says so plainly.

What we make

We run our own factory in Guangxi, working since 2008. Our moissanite is GRA D colour, VVS1, set in 925 sterling silver, 9K, 14K or 18K gold. Our lab grown diamonds carry IGI reports. Everything we sell sits between $17 and $2,020, with a median around $98 — which is the whole point of the range: a real stone at a price that does not require a financing plan.

Shipping is free over $99, otherwise $5.99, and returns run 30 days on unworn pieces in their original packaging. If you are still unsure which material suits you, tell us what the piece is for — daily wear, an engagement, a gift — and we will tell you which one we would put the money into.