Schäferite
| Schäferite | |
|---|---|
| General | |
| Category |
Phosphate mineral Berzeliite group Garnet structural group |
| Formula (repeating unit) | Ca2NaMg2[VO4]3 |
| Strunz classification | 08.AC.25 |
| Crystal symmetry |
Isometric hexoctahedral H-M symbol: (4/m32/m) Space group: I a3d |
| Unit cell | a = 12.427 Å, Z = 8 |
| Identification | |
| Formula mass | 496.57 g |
| Color | Red, orange-red |
| Crystal habit | Octahedral crystals |
| Crystal system | Cubic |
| Cleavage | None |
| Fracture | Conchoidal |
| Mohs scale hardness | 5 |
| Luster | Vitreous |
| Streak | Yellow |
| Diaphaneity | Transparent |
| Optical properties | Isotropic |
| Refractive index | n = 1.96 |
| References | [1][2] |
Schäferite is a rare vanadate mineral with chemical formula Ca2NaMg2[VO4]3. Schäferite is isometric, which means that it has three axes of equal length and 90° angles between the axes.[3] Schäferite is isotropic, meaning that the velocity of light is the same no matter which direction the light passes through.[2]
It was named after Helmut Schäfer (born 1931) who discovered it in a quarry on the Bellerberg volcano in Germany.[1] It is found only in the Eifel Mountains volcanic area near Mayen, Laacher See district of Germany.[1] It occurs within a xenolith in a leucite tephrite. It is the magnesium analogue of palenzonaite and is a member of the garnet structural group.[2]
References
- 1 2 3 Ralph, Jolyon and Ida Chau, 17 August 2010, "Schäferite." http://www.mindat.org/min-7279.html. Accessed 27 September 2010.
- 1 2 3 Barthelmy, David, 1997-2010, “Schäferite Mineral Data.” http://www.webmineral.com/data/Schaferite.shtml. Accessed 27 September 2010.
- ↑ Verlagsbuchhandlung, E.S. (1999) Schäferite, a new vanadium garnet. Neues Jahrbuch Fur Mineralogie,1, 123-134.
This article is issued from Wikipedia - version of the Tuesday, September 17, 2013. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.