Physical Properties |
|
| Chemical formula | ZnS |
| Class | Sulfide |
| Crystal system | Cubic |
| Habit | Combinations of tetrahedra, dodecahedra, and cubes Commonly forms cleavable masses |
| Color | Brown-orange-red Colorless when pure Brown Black Yellow |
| Hardness | 3.5 to 4 |
| Specific gravity | 4.0 |
| Cleavage | Perfect dodecahedral {110} |
| Fracture | Conchoidal |
| Luster | Adamantine Resinous |
| Transparency | Transparent to opaque |
| Streak | White to brown or yellow |
Optical Properties |
|
| PPL | Colorless to pale brown or yellow Extremely high relief Good cleavage |
| XPL | Isotropic |
| δ | None |
| Twinning | Polysnthetic twins are common |
Special properties |
May have faint garlic or sulfur smell, especially if powdered |
| after Perkins, 355-356 |
Sphalerite in Hand Sample
Three small hand samples
Sphalerite on fossiliferous chert
Sphalerite in Thin Section
Thin Section GigaPans
Sphalerite in plane polars
Sphalerite in crossed polars
Sphalerite, Plane Polars
Sphalerite in plane polarized light. Magnification: 40x Click here to watch this grain rotate uneventfully in XPL: https://youtu.be/h4vTVQOcEWk Click here to…
Sphalerite, Crossed Polars
As sphalerite is isotropic, this video is uneventful. Sphalerite in plane polarized light. Magnification: 40x Click here to watch this grain rotate in PPL: h…