Lab-grown diamonds and moissanite are not the same material, are not priced the same, and are not interchangeable. Here's a direct comparison on every variable that matters to a buyer.

What They Actually Are

Lab-grown diamond is pure carbon in a cubic crystal lattice — the same material as mined diamond, grown via HPHT or CVD processes. Moissanite is silicon carbide (SiC) — a different element, a different crystal structure, different optical properties. Both are lab-created. The similarity ends there.

Optical Properties — Where Moissanite Actually Differs

Diamond has a refractive index of 2.42 and dispersion (fire) rating of 0.044. Moissanite has a refractive index of 2.65–2.69 and dispersion of 0.104 — more than double diamond's fire. Moissanite produces more rainbow dispersion under direct light. Some buyers love this. Others find it looks artificial — the fire pattern is distinctive enough that experienced observers recognize it as not diamond.

Certification

Lab-grown diamonds are certified by IGI and GIA using the standard 4C framework. Moissanite is typically certified only by the manufacturer — not independently graded. For buyers who want verifiable, independently graded quality documentation, moissanite doesn't provide it.

Price — Where Moissanite Wins

A 2ct moissanite costs $400–$600. A comparable 2ct lab-grown diamond (VVS1, D-E color, IGI certified) costs $1,000–$1,800. Moissanite is meaningfully cheaper. If budget is the primary constraint and the optical differences don't concern you, moissanite is a legitimate choice. That's an honest answer.

The Decision Matrix

Factor	Lab Diamond	Moissanite
Material	Carbon (same as mined)	Silicon carbide (different)
Hardness	Mohs 10	Mohs 9.25–9.5
Fire	0.044 — classic	0.104 — intense rainbow
Independent cert	IGI / GIA	Manufacturer only
Price (2ct)	$1,000–$1,800	$400–$600

See the full collection at StudsDirect. Or read our guides on whether lab diamonds are real and how to choose clarity grade.