Skaergaardite
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| Skaergaardite | |
|---|---|
| General | |
| Category | Platinum group mineral |
| Formula | PdCu |
| IMA symbol | Skg[1] |
| Strunz classification | 1.AG.30 |
| Crystal system | Cubic |
| Crystal class | Hexoctahedral (m3m) H-M symbol: (4/m 3 2/m) |
| Space group | Pm3m |
| Unit cell | a = 3.0014(2) Å V = 27.0378 Å3, Z = 1 |
| Identification | |
| Color | Steel grey with a bronze tint |
| Crystal habit | Occurs as droplets, equant grains with rounded outlines, subhedral to euhedral crystals, and as irregular grains that vary in size from 2 to 75 micrometers, averaging 22 micrometers. |
| Tenacity | Sectile |
| Mohs scale hardness | 4 to 5 |
| Luster | Metallic |
| Streak | Black |
| Diaphaneity | Opaque |
| Specific gravity | 10.64 |
| Optical properties | Isotropic; no discernible internal reflections; color varying from bright creamy white to bright white. |
| Pleochroism | Non-pleochroic |
| Other characteristics | Typically found in composite microglobules in tholeitic gabbro. |
| References | [2][3][4] |
Skaergaardite is an intermetallic platinum group mineral with the general chemical formula PdCu. The mineral is named after its discovery location: the Skaergaard intrusion, Kangerdlugssuaq area, East Greenland. The mineral name was approved by the International Mineralogical Association in 2003. The mineral has also been reported in the Duluth intrusion in Minnesota and the Rum layered intrusion in Scotland.[3]
Skaergaardite is associated with igneous intrusions containing well-preserved, oxide-rich, tholeiitic gabbro. It is found as inclusions in titanian magnetite, ilmenite, pyroxenes, and plagioclase. Skaergaardite can occur as an inclusion by itself, but is more commonly found in composite microglobule inclusions of copper iron sulfide minerals and other precious metal bearing minerals.[3]
Crystallography and symmetry
The crystallography of skaergaardite was determined using x-ray powder diffraction data. It has an isometric (cubic) crystal system and a hexoctahedral crystal class (Hermann–Mauguin notation: 4/m32/m). Skaergaardite can appear in various forms including: droplets; cubic grains with rounded outlines; euhedral to subhedral grains; and irregular grains or aggregates.[2][3]