Moissanite vs Lab Diamond: What's the Difference?

Introduction

Both moissanite and lab-grown diamonds have become popular alternatives to mined diamonds — and for good reason. They're both ethical, both available in consistent quality, and both significantly more affordable than their mined counterparts. But they are very different stones, and understanding those differences will help you make the right choice for your jewelry project or purchase.

What Is a Lab Diamond?

A lab-grown diamond is chemically, physically, and optically identical to a mined diamond — it is pure carbon in a cubic crystal structure, with the same hardness (10 Mohs), the same refractive index (2.42), and the same optical properties. The only difference is origin: lab diamonds are grown in a controlled environment using either High Pressure High Temperature (HPHT) or Chemical Vapor Deposition (CVD) processes, rather than forming naturally underground over billions of years.

Lab diamonds are graded by the same gemological laboratories (GIA, IGI) using the same 4Cs system as mined diamonds.

What Is Moissanite?

Moissanite is a distinct gemstone — silicon carbide (SiC) — first discovered in a meteorite crater in 1893. It is not a diamond simulant or imitation; it is its own mineral with its own unique properties. All moissanite used in jewelry today is lab-grown, producing consistent quality and clarity.

Moissanite has a higher refractive index than diamond (2.65–2.69 vs. 2.42) and significantly more fire (dispersion of 0.104 vs. 0.044), making it one of the most brilliant gemstones available.

Moissanite vs Lab Diamond: Key Differences

Brilliance and Fire: Which Sparkles More?

Moissanite wins on raw brilliance and fire. Its higher refractive index means more light is bent and returned to the eye, and its dispersion is more than double that of diamond — producing vivid rainbow flashes that are especially striking in bright light.

Lab diamonds have the same optical properties as mined diamonds: beautiful, classic sparkle with a more subdued fire. Many buyers prefer the traditional look of diamond brilliance; others love moissanite's more dramatic sparkle. Neither is objectively better — it comes down to personal preference.

Hardness and Durability

Lab diamonds score a perfect 10 on the Mohs scale — the hardest material known. Moissanite scores 9.25, making it the second hardest gemstone used in jewelry. Both are extremely durable for everyday wear. For practical purposes — rings, earrings, pendants worn daily — the difference in hardness is negligible. Both stones will last a lifetime with normal care.

Price: The Biggest Practical Difference

This is where moissanite has a clear advantage. While lab diamonds are significantly cheaper than mined diamonds, they still command a substantial price — a 1ct lab diamond typically costs €500–1,500+ depending on quality. A comparable moissanite stone costs a fraction of that, often €50–€150.

For jewelry makers, this difference is significant: moissanite allows you to create high-quality, brilliant pieces at price points that open up a much wider market.

Ethics and Sustainability

Both moissanite and lab diamonds are ethical choices — neither involves mining, and both have a significantly lower environmental footprint than mined stones. If ethical sourcing is your primary concern, either option is a sound choice.

Will a Diamond Tester Tell Them Apart?

Standard thermal diamond testers will read both moissanite and lab diamond as “diamond” — both have high thermal conductivity. A multi-tester that measures electrical conductivity alongside thermal conductivity can distinguish them, as moissanite is a semiconductor while diamond is not. However, to the naked eye, neither can be distinguished from the other or from a mined diamond without specialist equipment.

Which Should You Choose?

• Choose moissanite if you want maximum brilliance and fire, the best value per millimeter, and a stone that performs beautifully in any setting
• Choose lab diamond if you want a stone that is chemically identical to diamond, carries GIA/IGI grading certification, or if your customer specifically wants a diamond

For jewelry makers focused on creating stunning, high-quality pieces at accessible price points, moissanite is often the more practical and commercially versatile choice.

Shop Loose Moissanite Stones

Browse our collection of visually inspected loose moissanite — available in a full range of cuts and sizes for your jewelry projects.