Put a moissanite stud, a cubic zirconia stud and a lab grown diamond stud side by side in a product photo and most people cannot tell them apart. They are not the same thing, and only one of them is a diamond.
Cubic zirconia
A synthetic crystalline form of zirconium dioxide, first produced commercially in the 1970s. It is the most affordable of the three by a wide margin. Cubic zirconia is noticeably softer than diamond, which in practice means the facet edges of a stone worn daily will gradually round off and the stone will look cloudier over a few years than it did new. For a pair of earrings — which do not take the knocks a ring takes — that process is slow.
Moissanite
Silicon carbide. It occurs naturally in tiny quantities in meteorite fragments, and every moissanite sold as jewelry is grown in a laboratory. It is considerably harder than cubic zirconia and close behind diamond on the Mohs scale, so it holds its edges and its polish.
Its more distinctive property is optical: moissanite has a higher dispersion than diamond, which is the technical way of saying it throws more rainbow-colored flashes. In a small stud this reads as extra liveliness. In a large stone under bright light, some people find it obviously different from diamond, and others prefer it.
Lab grown diamond
Chemically, physically and optically diamond — the same carbon lattice, grown in a reactor instead of underground. It is not a simulant. The Federal Trade Commission requires that it be clearly disclosed as laboratory-grown, which is why any honest listing says so plainly rather than hiding it in a specification table.
Comparing Listings Without Getting Confused
- "Diamond simulant" means it is not a diamond. So does "diamond-like", "CZ diamond" and any phrase that puts an adjective in front of the word.
- Carat weight on a simulant is not a like-for-like comparison. Moissanite is less dense than diamond, so a moissanite described as one carat is usually quoted as a diamond equivalent weight rather than an actual weight. Compare millimeter diameters instead — that is what your eye sees.
- "ctw" means the total across the pair, not per earring. A 2.0ctw pair of studs is two 1.0ct stones.
- A grading claim without a certificate is just a claim. Color and clarity grades mean something when an independent laboratory issued them and you can see the report.
Which to Buy
For earrings worn most days, moissanite is the practical middle: hard enough to stay bright, priced well below diamond. Cubic zirconia makes sense when you want a large look at a low price and accept that it will age. Lab grown diamond makes sense when you specifically want diamond.
Every listing on this store names the stone it uses. Moissanite pieces are grouped together if you want to compare within one material.