Gehlenite
| Gehlenite | ||
|---|---|---|
Mohs scale hardness 5–6 | | |
| Lustre | vitreous, greasy | |
| Streak | white, grey-white | |
| Birefringence | δ = 0.010 | |
Gehlenite, (Ca2Al[AlSiO7]), is a
TheAdolf Ferdinand Gehlen (1775–1815) by A.J. Fuchs in 1815.[4]
Geological occurrence
Gehlenite is found in
lamprophyres and possibly kimberlite pipes.[10]
Gehlenite has also been found on the comet 81P/Wild.[11]
Crystallography, composition and physical properties
Gehlenite is one of five, isostructural tetragonal crystal system minerals in the melilite group. The tetrahedral linkage within the structure is similar to that of an aluminosilicate framework structure[12] and was once considered a feldspathoid-like mineral[13] due to silica undersaturation.
Gehlenite has a
2V angle and has a characteristic 'ultrablue' birefringence.[12]
References
Wikimedia Commons has media related to Gehlenite.
- S2CID 235729616.
- ^ Deer et al., 1993
- ^ a b c Gehlenite: Gehlenite mineral information and data
- ^ Dana et al. 1997
- ^ Grossman L (1972) Condensation in the primitive solar nebula, Geochemica et Cosmochemica Acta, 36, 597–619
- ^ Exploring the Planets lecture by Archibald Reid. The University of Houston
- ^ Carmichael ISE, Turner FJ, Verhoogen J (1974) Igneous Petrology, 37
- ^ a b Le Maitre RW (2002), Igneous Rocks, 11, 153
- ^ Nixon PH (1987) Mantle Xenoliths, 102–103, 336, 450–451
- ^ Skinner EMW, Mahotkin IL, Grutter HS (1999) Melilite in Kimberlites, Proceedings of the International Kimberlite Conference, 7, 788–794
- ^ Mindat page for Comet Wild 2 (Comet 81P)
- ^ a b Louisnathan S (1969), Refinement of the crystal structure of gehlenite, Canadian Mineralogist, 10, 822–837
- ^ Best MG (2003), Igneous and Metamorphic Petrology (2nd Ed), 398, 693, 702–703