Hodgkinsonite
Hodgkinsonite is a rare zinc manganese silicate mineral Zn2MnSiO4(OH)2. It crystallizes in the monoclinic system and typically forms radiating to acicular prismatic crystals with variable color from pink, yellow-red to deep red. Hodgkinsonite was discovered in 1913 by H. H. Hodgkinson, for whom it is named in Franklin, New Jersey, and it is only found in that area.[1]
| Hodgkinsonite | |
|---|---|
 Hodgkinsonite from Franklin Mine, Franklin, New Jersey USA. The translucent and lustrous crystals reach 8 mm and the main crystal here is doubly terminated. | |
| General | |
| Category | Nesosilicate |
| Formula (repeating unit) | Zn2MnSiO4(OH)2 |
| Strunz classification | 9.AE.20 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | P21/a |
| Unit cell | a = 11.76, b = 5.31 c = 8.18 [Å]; β = 95.42°, Z = 4 |
| Identification | |
| Mohs scale hardness | 4 1⁄2 - 5 |
| Optical properties | Biaxial (-) |
| Refractive index | nα = 1.720 nβ = 1.741 nγ = 1.746 |
| Birefringence | δ = 0.026 |
| Dispersion | r < v moderate |
References
- Mineral Galleries Archived 2008-10-18 at the Wayback Machine. Accessed August 22, 2008.
- http://rruff.geo.arizona.edu/doclib/hom/hodgkinsonite.pdf Manual of Mineralogy
- http://webmineral.com/data/Hodgkinsonite.shtml Webmineral
- http://www.mindat.org/min-1913.html Mindat
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