Geerite
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| Geerite | |
|---|---|
 | |
| General | |
| Category | Sulfide mineral |
| Formula | Cu8S5 |
| IMA symbol | Gee[1] |
| Strunz classification | 2.BA.05c |
| Crystal system | Trigonal |
| Crystal class | 32, 3m, 3m |
| Unit cell | a = 3.83 Å, c = 46.84 Å; Z = 1 |
| Identification | |
| Formula mass | 668.70 g/mol |
| Color | Bluish white in reflected light |
| Crystal habit | Platy – sheet forms (e.g. micas); pseudocubic |
| Mohs scale hardness | 3.5-4 |
| Luster | Metallic |
| Diaphaneity | Opaque |
| Specific gravity | 5.61 |
| Pleochroism | Weak |
| References | [2][3][4] |
Geerite is a copper sulfide mineral with the chemical formula Cu8S5. The mineral is named after the original collector, Adam Geer, of Utica, New York, US.
Geerite is in the crystal class 3. This means that the crystal could be inverted and then rotated by 120 degrees to return to its original position. The optical class of geerite is unknown. Geerite is anisotropic which means that it will show interference colors when it is rotated in cross polarized light and that the mineral has different properties in different directions.
