Seifertite
| Seifertite | ||
|---|---|---|
Specific gravity 4.294 | | |
| References | [2][3] | |
Seifertite is a
silica. It has only been found in Martian[4][5] and lunar meteorites,[6] where it is presumably formed from either tridymite or cristobalite – other polymorphs of quartz – as a result of heating during the atmospheric re-entry and impact to the Earth, at an estimated minimal pressure of 35 GPa. It can also be produced in the laboratory by compressing cristobalite in a diamond anvil cell to pressures above 40 GPa. The mineral is named after Friedrich Seifert (born 1941), the founder of the Bayerisches Geoinstitut at University of Bayreuth, Germany, and is officially recognized by the International Mineralogical Association.[4][5][7][8]
Seifertite forms micrometre-sized crystalline
orthorhombic symmetry and Pbcn or Pb2n space group. Its lattice constants a = 4.097, b = 5.0462, c = 4.4946, Z = 4 correspond to the density of 4.294 g/cm3, which is among the highest for any forms of silica (for example, the density of quartz is 2.65 g/cm3).[3][4][5][8] Only stishovite has a comparable density of about 4.287 g/cm3.[9]
See also
References
- S2CID 235729616.
- ^ Seifertite at Webmineral
- ^ a b Seifertite at Mindat.
- ^ .
- ^ S2CID 129400258.
- .
- ^ The official IMA-CNMNC List of Mineral Names Archived 2011-02-28 at the Wayback Machine, International Mineralogical Association.
- ^ a b Seifertite: A new natural very dense post-stishovite polymorph of silica, University of Bayreuth.
- ^ Stishovite summary, Handbook of mineralogy.
| Crystalline | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Cryptocrystalline | |||||||||
| Amorphous | |||||||||
| Miscellaneous | |||||||||
| Notable varieties |
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