Quick answer
The short version of moissanite vs diamond: a diamond is pure carbon and the hardest natural material (10 on the Mohs scale). Moissanite is silicon carbide, nearly as hard (9.25), more brilliant, with about 2.4 times the rainbow fire, for a small fraction of the price. Choose a diamond if the word itself matters to you. Choose moissanite for the most sparkle per dollar.
From across a dinner table, a well-cut moissanite and a diamond look like the same thing: a bright white stone catching the light. Up close they behave differently, and the price gap between them is enormous.
Below we compare them on what you will actually notice: sparkle, hardness, color, how to tell them apart, price and resale. Comparing moissanite with a lab-grown diamond instead? Read moissanite vs lab-grown diamond.
Key takeaways
- A diamond is carbon, hardness 10. Moissanite is silicon carbide, hardness 9.25, harder than sapphire and ruby.
- Moissanite bends more light (refractive index 2.65 vs 2.42) and splits it into more color (dispersion 0.104 vs 0.044).
- A standard thermal diamond tester reads moissanite as diamond. A multi-tester, or a jeweler with a loupe, tells them apart.
- A 1ct-look moissanite ring costs hundreds of dollars, not thousands. Neither stone is an investment.
What is the difference between moissanite and a diamond?
A diamond is carbon crystallized under enormous heat and pressure. According to GIA, most natural diamonds formed 150 to 200 km below the surface, and some are more than 3 billion years old. They are mined, sorted, cut and graded, and the rarest colorless stones command the highest prices.
Moissanite is silicon carbide. The French chemist Henri Moissan found tiny crystals of it in 1893, in fragments of the Canyon Diablo meteorite in Arizona, and first took them for diamond. (Moissan later won the 1906 Nobel Prize in Chemistry, for isolating fluorine.) Natural moissanite is far too rare to cut into jewelry, so every moissanite you can buy is grown in a lab. Gem-quality stones reached jewelers in the late 1990s.
So moissanite is not a fake diamond, and it does not try to be one chemically. It is a different gem that happens to look very close. More on that in Is moissanite real?
Moissanite vs diamond, side by side
The numbers that matter, in one table. Moissanite figures are for colorless stones; every white stone at Daellia is D color, VVS1.
| Moissanite | Diamond | |
|---|---|---|
| Material | Silicon carbide (SiC) | Carbon |
| Origin | Grown in a lab | Mined (lab-grown diamonds also exist) |
| Hardness (Mohs) | 9.25 | 10 |
| Refractive index (brilliance) | 2.65 to 2.69 | 2.42 |
| Dispersion (fire) | 0.104 | 0.044 |
| Density | About 3.21 g/cm3, so about 10% lighter | About 3.52 g/cm3 |
| Optical character | Doubly refractive | Singly refractive |
| Thermal diamond tester | Reads as diamond | Reads as diamond |
| 1ct-look solitaire ring | Hundreds of dollars, complete | Thousands of dollars for the stone alone |
| Resale value | Very low | A fraction of the retail price |
Sources: GIA, Britannica. Moissanite figures are for colorless stones.
Does moissanite sparkle more than a diamond?
Yes. Two numbers explain it. The refractive index, how strongly a gem bends light, is 2.65 to 2.69 for moissanite and 2.42 for diamond, so moissanite sends more light back to your eye. The dispersion, how much a gem splits white light into colors, is 0.104 against 0.044: about 2.4 times more fire.
What you see in real life: in sunlight or under restaurant spotlights, moissanite throws flashes of pink, green and violet. A diamond flashes too, but its light reads whiter and calmer. The larger the stone, the more obvious the difference. Some people love the extra color, others prefer the quieter look of a diamond. It is a matter of taste, not of quality.
One honest note: moissanite is doubly refractive. Looking through the stone at certain angles, or under a 10x loupe, you can see the back facet edges doubled. Good cutters orient the stone to keep this out of the face-up view, and most people never notice it.
Is moissanite as durable as a diamond?
Almost. A diamond scores 10 on the Mohs scale, moissanite 9.25: harder than sapphire and ruby (9), and well above cubic zirconia (about 8 to 8.5). The scale is not linear, so the step from 9 to 10 is bigger than it looks. A diamond really is much harder to scratch.
For daily wear, both are more than hard enough. Everyday dust contains quartz, at 7 on the scale, and quartz cannot scratch either stone. What wears first on any ring is the metal: prongs thin over the years and plating softens. Both stones can chip if they take a hard knock on an exposed edge, which is why prongs deserve a check once a year.
Good to know
Moissanite does not cloud, yellow or lose its sparkle with age. When it looks dull, it is a film of skin oil, lotion and soap, gone after a wash in warm water with a drop of dish soap. See does moissanite get cloudy and our jewelry care guide.
Moissanite vs diamond: color and clarity
Diamonds are graded on a color scale from D (colorless) to Z (light yellow or brown). The closer to D, the rarer and the more expensive the stone. Clarity runs from flawless to included, depending on the tiny crystals and feathers inside.
Moissanite borrowed the same vocabulary. The first stones on the market had a faint tint, around J to K on the diamond scale, and fully colorless D to F moissanite arrived in 2015. Every white stone at Daellia is D color, the top of the scale, with VVS1 clarity: any inclusion is practically invisible even at 10x magnification. Because the stones are grown, that top grade costs little extra, which is never the case with diamonds.
Moissanite is also grown in color, from pink to black. See our colored moissanite tennis bracelets and black moissanite jewelry.
How can you tell moissanite from a diamond?
- Thermal tester: no help. Moissanite conducts heat much like diamond, so the common pen tester reads it as diamond. Details in does moissanite pass a diamond tester.
- Multi-tester: yes. It also measures electrical conductivity, which separates the two in seconds.
- Loupe: a jeweler looking through the side of the stone can spot doubled facet edges in moissanite.
- Light: in direct sun, moissanite shows more rainbow color.
- Weight: at the same size, moissanite weighs about 10% less, which is why it is sold by diamond equivalent weight (DEW).
About certificates
Some moissanite ships with a GRA card. It describes a moissanite (size, color, clarity). It is not a diamond certificate and it is not issued by GIA. At Daellia, pieces marked "GRA report included" come with their card; see our quality promise.
Moissanite vs diamond price
This is where the two part ways. A 1 carat natural diamond of good color and clarity typically costs thousands of dollars for the loose stone, before the setting. A moissanite of the same size costs a small fraction of that: a complete ring, stone and metal included, costs hundreds of dollars, not thousands.
Budget shapes size. In The Knot's 2026 Real Weddings Study, couples who chose a lab-grown center stone went bigger (2.0 carats on average) than couples who chose a natural one (1.6 carats). Moissanite pushes that logic further: a 2ct or 3ct look stays within reach.
A 1ct look and bigger, in moissanite
Sirius Moissanite Solitaire RingRound solitaire in six prongs, 6.5mm (1ct) to 11mm (5ct).See the piece
Olympe Oval Moissanite Engagement RingA 2ct DEW oval on a slim 14K gold filled band.See the piece
Sirius Moissanite Solitaire StudsSolitaire studs from 3mm to 9mm: the easiest way to try the look.See the piece
Do moissanite and diamonds hold their value?
Not well, either of them. A diamond usually resells for a fraction of what you paid at retail, and ever cheaper lab-grown diamonds add pressure on prices. Moissanite has very little resale value. The difference is how much you put in: spend less up front and there is less to lose. Buy the stone you love wearing, not an investment.
On sourcing: natural diamonds are mined, and the Kimberley Process certifies rough diamonds as conflict-free under its own definition. Moissanite is grown in a lab, so there is no mining involved. Growing it takes energy, as growing a lab diamond does.
A diamond is a diamond. Moissanite is a different gem with more fire. Both are the right choice when you know which one you are buying.The Daellia Journal
Moissanite or diamond: which should you choose?
| If you care most about | Choose | Why |
|---|---|---|
| The word “diamond” and tradition | Diamond | Nothing else is a diamond |
| Maximum sparkle and fire | Moissanite | About 2.4 times the dispersion |
| The hardest stone possible | Diamond | 10 on the Mohs scale versus 9.25 |
| The biggest look for your budget | Moissanite | A 2ct or 3ct look stays affordable |
| A calm, white glow | Diamond | Less colored flash |
| Everyday studs without worry | Moissanite | A lost stud is easy to replace |
| Resale value | Neither | Both resell for much less than retail |
Still unsure? Try moissanite in a low-stakes piece first. A pair of Sirius solitaire studs shows you how the fire looks on you, every day. For rings, browse our moissanite engagement rings or read the engagement ring buyer's guide, and check your size with the ring size chart.
See the fire for yourself
Solitaire studs, rings and tennis bracelets in D color, VVS1 moissanite, set in sterling silver or 14K gold filled.
Shop best sellersFrequently asked questions
Is moissanite a fake diamond?
No. A fake, or simulant, imitates a diamond with a cheaper material such as glass or cubic zirconia. Moissanite is a gemstone in its own right (silicon carbide), first found in a meteorite in 1893. It looks close to a diamond, but it has its own chemistry, more fire and its own name. Every moissanite used in jewelry is lab-grown.
Can a jeweler tell moissanite from a diamond?
Yes, usually in seconds. A multi-tester that measures electrical conductivity flags moissanite, and under a loupe a jeweler may see doubled facet edges. A basic thermal pen tester cannot, because moissanite conducts heat much like diamond. Without tools, most people cannot tell them apart at a normal distance.
Will moissanite last as long as a diamond?
For jewelry, yes. At 9.25 on the Mohs scale, moissanite resists scratches from everyday dust and keeps its polish and brilliance for life. It does not cloud or change color. The metal setting will need care long before the stone does, so have prongs checked once a year.
Does moissanite look cheap next to a diamond?
Not when it is well cut and colorless. The first moissanite on the market had a faint tint, which shaped its early reputation. A D color, VVS1 stone today looks bright white. The main visible difference is more rainbow fire in strong light, which some people prefer and others find too lively.
Is moissanite worth it for an engagement ring?
For many couples, yes. It is hard enough for daily wear, stays brilliant, and frees budget for a larger stone or the wedding itself. If the tradition of a diamond matters to you or your partner, talk about it first: the right ring is the one you are both happy to see every day.
Keep reading
Written by the Daellia Journal team, Paris. We write about moissanite, metals and the stories behind fine jewelry so you can buy with confidence. Read our moissanite guide or our story.
