Geerite
| Geerite | |
|---|---|
| General | |
| Category | Sulfide |
| Chemical formula | Cu8S5 |
| Strunz classification | 02.BA.05c |
| Crystal symmetry | Trigonal 3 rhombohedral |
| Unit cell | a = 3.83 Å, c = 46.84 Å; Z = 1 |
| Identification | |
| Molar mass | 668.70 gm |
| Color | Bluish white in reflected light |
| Crystal habit | Platy - sheet forms (e.g. micas), pseudocubic |
| Crystal system | Trigonal |
| Mohs scale hardness | 3.5-4 |
| Luster | Metallic |
| Diaphaneity | Opaque |
| Specific gravity | 5.61 |
| Pleochroism | Weak |
| References | [1][2][3] |
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, USA.
Contents |
[edit] Crystallography
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
[edit] Discovery and occurrence
It was first described in 1980 for an occurrence as thin coatings or platelets replacing sphalerite in the type locality in De Kalb Township, Saint Lawrence County, New York. The geologic setting that it occurs in is in the replacement of Sphalerite. [1] It has also been used to study crystal structure and bonding in copper sulfides. [1]
[edit] See also
[edit] References
- http://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Geerite
- Goble, R.J.(1985) The Relationship Between Crystal Structure, Bonding, and Cell Dimension in the Copper Sulfides. Canadian Mineralogist, 23, 61-76.
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