Pyrite vs Marcasite
Pyrite and Marcasite are easy to confuse. Here’s how they stack up on the properties that actually separate them.
| Pyrite | Marcasite | |
|---|---|---|
| Colour | Gold, Yellow | Gold, Gray, White, Brown, Yellow |
| Mohs hardness | 6–6.5 | 6–6.5 |
| Lustre | Metallic, glistening | Metallic |
| Streak | Greenish-black to brownish-black | Dark-grey to black |
| Crystal system | Cubic | Orthorhombic |
| Transparency | Opaque | Opaque |
| Cleavage | Indistinct on {001}; partings on {011} and {111} | Cleavage: {101}, rather distinct; {110} in traces |
| Fracture | Very uneven, sometimes conchoidal | Irregular/Uneven |
| Chemical formula | FeS 2 | FeS 2 |
| Specific gravity | 4.95–5.10 | 4.875 calculated, 4.887 measured |
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Frequently asked questions
What's the easiest way to tell Pyrite from Marcasite?
Compare lustre, streak and crystal habit side by side — colour alone won't settle it.