Moissanite vs Diamond: An Honest Comparison
Moissanite and diamond look alike at a glance, and both are hard enough to wear every day. They are different gemstones, though, and each has trade-offs. Here is a plain comparison to help you choose.
What each stone is
Diamond is pure carbon. It can be mined, or grown in a laboratory (a lab-grown diamond is still a real diamond).
Moissanite is silicon carbide. It was first found in a meteorite crater in 1893 and is extremely rare in nature, so the moissanite used in jewellery is lab-created. It is its own gemstone: not a diamond, and not cubic zirconia.
Side by side
| Moissanite | Diamond | |
|---|---|---|
| Made of | Silicon carbide | Carbon |
| Hardness (Mohs) | 9.25 | 10 |
| Refractive index | 2.65 to 2.69 | 2.42 |
| Fire (dispersion) | 0.104 | 0.044 |
| Price | A fraction of diamond | Highest |
Sparkle: more fire, a different look
Moissanite bends light more strongly than diamond and splits it into colours about twice as much. In practice that means more flashes of rainbow colour, especially in sunlight and in larger stones. Diamond's sparkle looks whiter and more subtle. Neither is better; it comes down to which look you prefer. Many people love moissanite's extra fire, while others find it a little too lively in very large stones.
Durability for everyday wear
Moissanite scores 9.25 on the Mohs hardness scale, just below diamond's 10 and harder than sapphire. It resists scratches well and suits a ring you wear every day. Like any stone, it can still chip from a hard knock, so take rings off for heavy work or the gym.
Colour and clarity
Most moissanite sold today is described as colourless, often graded D to F on the same letter scale used for diamonds. Because it is made in a lab, it is also usually very clean inside. On our listings, colour, clarity and any GRA certificate are as stated by our supplier; we have not independently verified them.
Can people tell the difference?
To the naked eye, most people cannot. Up close, the stronger rainbow fire is the usual giveaway. A basic thermal diamond tester can read moissanite as diamond, while a moissanite tester, which checks electrical conductivity, tells them apart. We always sell moissanite as moissanite.
Price
This is the biggest difference. A moissanite of a given size costs a small fraction of a diamond of the same size, so many couples choose a larger stone, or put the savings towards the wedding.
Which should you choose?
- Choose moissanite if you want a large, bright stone with lots of fire at a gentle price.
- Choose diamond if the name and tradition matter most to you, or you prefer a whiter, quieter sparkle.
Our engagement rings are moissanite set in 925 sterling silver, in plain silver or plated finishes. Browse moissanite engagement rings, see the 1ct moissanite solitaire pictured above, or take the 1-minute ring quiz on our Engagement Rings page.
Want the short version? Read our moissanite guide, and check your size with the ring size guide before you order.