Emerald vs Peridot
Emerald and Peridot are commonly confused, and 3 measured properties separate them — crystal system most clearly.
Emerald vs Peridot
Emerald
Beryl coloured green by chromium — and the one major gemstone whose inclusions are expected rather than a fault.
Peridot
Gem olivine, and one of very few gemstones that occurs in only one colour — including specimens that arrived from space.
| Property | Emerald | Peridot |
|---|---|---|
| Crystal system Categorical values can be listed side by side but not ordered or subtracted. | hexagonal | orthorhombic |
| Density | 2.67–2.78 g/cm³ | 3.27–3.48 g/cm³ higher |
| Mohs hardness Mohs hardness is an ordinal scale: values can be ranked, but differences and ratios between them are not meaningful. | 7.5–8 higher | 6.5–7 |
Why these get confused
several famous historic 'emeralds' in European treasuries have turned out to be peridot, which is a softer, yellower green and far more strongly doubly refractive
The confusion is a real and documented one, not a resemblance we have invented.