A lab-grown diamond is a real diamond, so it is harder (Mohs 10 against moissanite's 9.25) and reads as diamond on every tester. Moissanite is a different gemstone, silicon carbide, with more fire, and it costs far less: a 1 carat solitaire ring is $79 at Mariqe, against about $670 to $1,500 for a loose 1 carat lab-grown diamond.
Moissanite and lab-grown diamond side by side
| Moissanite | Lab-grown diamond | |
|---|---|---|
| Material | Silicon carbide | Carbon, the same as natural diamond |
| Hardness (Mohs) | 9.25 | 10 |
| Refractive index | 2.65 | 2.42 |
| Dispersion (fire) | 0.104 | 0.044 |
| Standard diamond tester | Thermal testers can read it as diamond. Electrical conductivity and moissanite-specific testers tell them apart. | Reads as diamond, because it is diamond |
| Independent grading | GIA does not grade moissanite. Mariqe includes a GRA report. | Graded by GIA and IGI |
| Price, 1 carat | $79 to $99 for a finished Mariqe solitaire ring | About $670 to $1,500 for a loose stone |
Diamond prices are from thediamondprice.com (21 September 2026, G to H colour, VS2 clarity) and Beyond Carat (March 2026, D to F colour, VVS to VS1 clarity). Mariqe prices were checked on the product pages on 21 September 2026 and change during sales.
Is moissanite a lab-grown diamond?
No. Both are made in laboratories, but they are different materials. A lab-grown diamond is carbon with the same crystal structure as a mined diamond. Moissanite is silicon carbide. Henri Moissan first identified it in 1893 in samples from a meteorite crater in Arizona, and at first he mistook it for diamond. Natural moissanite is far too scarce for jewellery, so the moissanite in jewellery today, including every Mariqe stone, is grown in a laboratory.
Where lab-grown diamond wins
- Hardness. Diamond is 10 on the Mohs scale and moissanite is 9.25. Both are hard enough for daily wear, but diamond is the harder of the two.
- It is diamond. Every diamond tester will confirm it, and nobody can question what it is.
- Independent grading. GIA and IGI grade lab-grown diamonds. GIA does not grade moissanite, and Mariqe's stones come with a GRA report, which is a record of the stone's specifications rather than an independent valuation. Our guide to GRA certificates explains the difference.
- A more familiar sparkle. Diamond shows white and grey flashes. Moissanite's higher dispersion adds more rainbow-coloured flashes, especially in larger stones. Some people love that, and others prefer the look of diamond.
Where moissanite wins
- Price. Lab-grown diamond prices have fallen sharply since 2020, and the gap has narrowed. It is still large for a finished piece. A 3 carat lab-grown diamond costs roughly $4,000 to $10,000 as a loose stone (Beyond Carat, March 2026). A 3 carat Mariqe Eterna solitaire ring is $148 in platinum plated silver and $168 in 18k gold plated silver.
- Size for the money. A larger stone is realistic on a modest budget.
- Fire. Moissanite's dispersion is 0.104 against diamond's 0.044, so it throws more colour.
The price difference is not only the stone. Mariqe's pieces are 925 sterling silver with platinum or 18k gold plating, not solid gold, and that keeps the price low. A lab-grown diamond in a solid gold setting is a different product at a different price.
How they look and wear in practice
Both stones are colourless and both are usually cut as round brilliants, so from a distance they are hard to tell apart. Up close there are two differences. Moissanite is doubly refractive, so in larger stones you may see facet edges appear doubled when you look through the stone at an angle. Diamond is singly refractive and does not do this. Moissanite also throws more coloured flashes, as the dispersion figures above suggest.
Grade affects diamond prices far more than it affects moissanite prices. A 1 carat lab-grown diamond costs $670 or $1,500 depending largely on its colour and clarity grade, while moissanite is normally sold at one top grade, so its price follows size and metal. For everyday wear, the setting matters as much as the stone. Plated silver can lose its plating with long daily use whatever stone sits in it, so wear and care depend on the metal as well as the gem.
Which should you choose?
Choose a lab-grown diamond if you want a diamond in every technical sense, you want the hardest stone, or independent grading matters to you and your budget allows it. Choose moissanite if you want a larger, colourless stone for less, you like a livelier sparkle, and you are comfortable that it is its own gemstone, not a diamond.
What this means for you
Neither stone is the wrong choice. The honest question is what matters most to you: the material, the grading, or the size and price. If it is the last, moissanite gives you more for your budget. If it is one of the first two, a lab-grown diamond is a fair answer, and we would rather you buy what suits you.
Eterna Solitaire Ring
Six-prong round moissanite solitaire in 925 sterling silver with platinum or 18k gold plating. Choose 1, 2 or 3 carat. From $79, with a Lifetime Moissanite Warranty.
See sizes and pricesFrequently asked questions
Is moissanite the same as a lab-grown diamond?
No. Both are grown in laboratories, but a lab-grown diamond is carbon and moissanite is silicon carbide. They are different gemstones with different hardness, sparkle and price.
Which is harder, moissanite or a lab-grown diamond?
A lab-grown diamond is harder, at 10 on the Mohs scale against 9.25 for moissanite. Both are suitable for everyday wear.
Is moissanite cheaper than a lab-grown diamond?
Yes. A loose 1 carat lab-grown diamond costs roughly $670 to $1,500 in 2026, while a finished 1 carat Mariqe moissanite solitaire ring is $79 to $99. Lab-grown diamond prices have fallen, so the gap is smaller than it was, but it is still large.
Can a diamond tester tell moissanite from a lab-grown diamond?
A standard thermal diamond tester can read moissanite as diamond. Electrical conductivity testers and moissanite-specific testers can tell them apart, and a lab-grown diamond reads as diamond on all of them because it is diamond.