16.65: Sphalerite
- Page ID
- 6495
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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 |
Figure \(\PageIndex{1}\): Round Brilliant Sphalerite
Photo courtesy of
Rick Martin, Art Cut Gems