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-256921.jpg
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
CategoryNesosilicate
Formula
(repeating unit)		Zn2MnSiO4(OH)2
Strunz classification9.AE.20
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP21/a
Unit cella = 11.76, b = 5.31
c = 8.18 [Å]; β = 95.42°, Z = 4
Identification
Mohs scale hardness4+1⁄2 - 5
Optical propertiesBiaxial (-)
Refractive indexnα = 1.720 nβ = 1.741 nγ = 1.746
Birefringenceδ = 0.026
Dispersionr < v moderate

This article uses material from the Wikipedia article
 Metasyntactic variable, which is released under the 
Creative Commons
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Note

This article uses material from the Wikipedia article
 Metasyntactic variable, which is released under the 
Creative Commons
Attribution-ShareAlike 3.0 Unported License.