Moissanite vs Lab-Grown Diamond: Which Should You Buy?
Moissanite and lab-grown diamonds are both ethically sourced, lab-created alternatives to mined diamonds — but they are fundamentally different gemstones. Lab-grown diamonds are chemically identical to mined diamonds (pure carbon). Moissanite is silicon carbide, a completely different mineral with higher brilliance and 60-80% lower cost.
This guide from The Real Jewelry Company explains every difference so you can make the right choice for your budget and style.
Side-by-Side Comparison
| Property | Moissanite | Lab-Grown Diamond |
|---|---|---|
| Chemical Composition | Silicon Carbide (SiC) | Pure Carbon (C) |
| Brilliance | Higher (RI 2.65-2.69) | Lower (RI 2.42) |
| Fire / Rainbow Flashes | 2.4x more than diamond | Standard diamond fire |
| Hardness | 9.25 Mohs | 10 Mohs |
| 1ct Price | $200 - $600 | $800 - $3,000 |
| Diamond Tester | Passes thermal testers | Passes all testers |
| Resale Value | Minimal | Low (declining market) |
| Grading | D-color, IF-VVS1 standard | IGI/GIA certified, varies |
| Environmental Impact | Very low | Moderate (energy-intensive) |
The Price Gap Is Closing — But Moissanite Still Wins
Lab-grown diamond prices have dropped dramatically since 2020 as production scaled up. A 1-carat lab diamond that cost $5,000 in 2020 now costs $800-$1,500 in 2026. But moissanite still costs 60-80% less for equivalent visual impact.
For pieces with many stones — like tennis chains and tennis bracelets — the cost difference is massive. A 10ct moissanite tennis bracelet in solid gold might cost $2,000-$5,000. The same piece with lab diamonds would run $8,000-$15,000.
Brilliance: Moissanite Has More Fire
Moissanite has a higher refractive index (2.65-2.69 vs 2.42) and 2.4x more dispersion than diamond. This means moissanite produces more colorful rainbow flashes, especially in sunlight. Lab-grown diamonds produce the same white-light sparkle as mined diamonds.
Which looks "better" is subjective. Some people love moissanite's extra fire. Others prefer diamond's more understated brilliance. Both are stunning in person.
Hardness: Lab Diamond Wins (But It Doesn't Matter)
Lab-grown diamond scores a perfect 10 on the Mohs hardness scale. Moissanite scores 9.25. In practical terms, both are harder than anything you will encounter in daily life. Both resist scratching, chipping, and clouding. Both are lifetime stones.
Which Should You Choose?
Choose moissanite if:
- You want the most brilliance and fire for your money
- You are buying a multi-stone piece (tennis chain, bracelet, earrings) where cost multiplies
- You prioritize value — moissanite gives the biggest visual impact per dollar
- You like the look of extra rainbow fire
Choose lab-grown diamond if:
- It is important to you that the stone is technically "a real diamond"
- You prefer diamond's specific light return pattern
- You want IGI/GIA certification on each stone
- You are buying a single-stone piece like a solitaire engagement ring
At The Real Jewelry Company, we carry both. Browse our moissanite collection and lab-grown diamond collection to compare in person. Every piece ships free.
Frequently Asked Questions
Are lab-grown diamonds the same as moissanite?
No. Lab-grown diamonds are chemically identical to mined diamonds — pure carbon crystallized in a lab. Moissanite is silicon carbide (SiC), a completely different mineral. They look similar but have different optical properties, hardness, and price points.
Will a jeweler know if I have moissanite instead of a lab diamond?
Not without specialized testing equipment. Both stones look nearly identical to the naked eye and under standard magnification. A moissanite-specific electrical conductivity tester is required to distinguish them.
Do lab-grown diamonds hold their value?
Lab-grown diamond resale values have been declining as production increases and prices drop. Neither moissanite nor lab-grown diamonds are good "investments" — both should be purchased for beauty and enjoyment, not resale value.
Which is more ethical — moissanite or lab-grown diamond?
Both are ethical alternatives to mined diamonds. Moissanite has a slightly smaller environmental footprint because silicon carbide production requires less energy than the high-pressure, high-temperature (HPHT) or chemical vapor deposition (CVD) processes used for lab diamonds.