Understanding the difference
Lab grown and natural diamonds are the same material: crystallised carbon, with the same hardness, sparkle and chemistry. What differs is their origin. One is grown in a laboratory in a matter of weeks; the other formed deep underground, typically one to three and a half billion years ago, and was later mined.
Moissanite is a different gemstone, made of silicon carbide. It is slightly less hard than diamond and shows more coloured fire.
Side by side
Lab grown diamond vs moissanite vs natural diamond
| Property |
Lab grown diamondShop
|
MoissaniteShop
|
Natural diamond
|
|---|---|---|---|
| Material | Diamond (carbon) | Silicon carbide | Diamond (carbon) |
| Origin | Grown in a laboratory (CVD or HPHT) | Created in a laboratory | Formed in the Earth, then mined |
| Hardness (Mohs) | 10 | 9.25 | 10 |
| Refractive indexHigher means more brilliance | 2.42 | 2.65 to 2.69 | 2.42 |
| Dispersion (fire)Higher means more rainbow flashes | 0.044 | 0.104 | 0.044 |
| Specific gravity | 3.52 | 3.21 | 3.52 |
| Refraction | Single | Double | Single |
| Same properties as a natural diamond | Yes | No | Yes |
| Suited to everyday wear | Yes | Yes | Yes |
| Independent grading report | Common (e.g. IGI) | Rare | Common (e.g. GIA, IGI) |
| Relative price, same size | Lower | Lowest | Highest |
Values are typical gemmological figures. Mohs hardness measures scratch resistance on a scale of 1 to 10.
What is a lab grown diamond?
Chemically and physically, lab grown diamonds are diamonds; only their origin differs. They are grown either under high pressure and high temperature (HPHT), similar to the conditions deep in the Earth, or layer by layer from a carbon-rich gas (chemical vapour deposition, CVD), and are graded on the same 4Cs as mined diamonds.
What is moissanite?
Moissanite is silicon carbide. It occurs in nature only in tiny amounts, first identified in a meteorite crater, so the moissanite used in jewellery is created in a laboratory. It rates 9.25 on the Mohs scale and is known for strong rainbow fire.
What is a natural diamond?
A natural diamond formed under great heat and pressure deep in the Earth, was carried towards the surface by volcanic eruptions and was then mined. Each stone is graded on cut, colour, clarity and carat.
Need help?
Comparison questions
No. Moissanite is silicon carbide, a different mineral. It looks similar to a diamond but shows more coloured fire and is slightly less hard.
Not by eye. Gem laboratories use specialised instruments to identify the origin, and the grading report states it.
Both diamonds rate 10 on the Mohs hardness scale and moissanite 9.25, so all three are well suited to everyday wear.
Growing a diamond takes weeks and needs no mining, which generally lowers the price for the same size and quality.
Larger lab grown diamonds are usually graded by an independent laboratory such as IGI. The product page shows which report comes with your stone.