Hodgkinsonite

Hodgkinsonite
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	Zn2MnSiO4(OH)2
IMA symbol	Hgk
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

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

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.
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

External links

http://franklin-sterlinghill.com/palache/hodgkinsonite.stm

[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.

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