Hodgkinsonite

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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
IMA symbolHgk[1]
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+12 - 5
Optical propertiesBiaxial (-)
Refractive indexnα = 1.720 nβ = 1.741 nγ = 1.746
Birefringenceδ = 0.026
Dispersionr < v moderate

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.[2]

References[edit]

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ Mineral Galleries Archived 2008-10-18 at the Wayback Machine. Accessed August 22, 2008.

External links[edit]