Sphalerite
From The Gemology Project
| Sphalerite | |
|---|---|
| Chemical composition | (Zn,Fe)S |
| Crystal system | Cubic |
| Habit | Tetrahedral or dodecahedral |
| Cleavage | Perfect in 6 directions; easily developed |
| Fracture | Concoidal to uneven |
| Hardness | 3.5-4.0 |
| Optic nature | Isotropic |
| Refractive index | 2.368 - 2.50 (increases with Fe content) |
| Specific gravity | 3.95-4.10 |
| Lustre | Adamantine to Subadamantine |
Round Brilliant Sphalerite
Photo courtesy of
Rick Martin, Art Cut Gems
Photo courtesy of
Rick Martin, Art Cut Gems
