Crystallized plates of reddish-brown, silver metallic-lustre hisingerite crystals
CategorySilicate mineral
(repeating unit)
FeIII2Si2O5(OH)4 · 2 H2O
IMA symbolHsg[1]
Strunz classification9.ED.10
Crystal systemMonoclinic
Unknown space group
Unit cella = 5.4, b = 9.03
c = 14.99 [Å]; β = 98.32°; Z = 4
ColorBlack, brownish-black
Crystal habitMassive, compact; acicular, may be minutely spherical.
Mohs scale hardness2.5 - 3.0
LusterVitreous, resinous, greasy
StreakYellowish brown, green
DiaphaneityTransparent to translucent
Specific gravity2.43 - 2.67
Optical propertiesBiaxial (-)
Refractive indexnα = 1.715 nγ = 1.730
Birefringenceδ = 0.015

Hisingerite is an iron(III) phyllosilicate mineral with formula FeIII2Si2O5(OH)4 · 2 H2O. A black or dark brown, lustrous secondary mineral, it is formed by the weathering or hydrothermal alteration of other iron silicate and sulfide minerals.[2]

It was first described in 1751 by A.F. Cronstedt from Väster Silvberg, Dalarna, Sweden (under the name “kolspeglande järnmalm”), and in 1810 by W. Hisinger from the Gillinge iron mine, Södermanland, Sweden (“svart stenart”, later “gillingit”).[5] In 1828 it was found at an occurrence in Riddarhyttan, Vastmanland, Sweden. It was named after Wilhelm Hisinger (1766–1852), a Swedish chemist.[4]

There are also aluminian hisingerite variety in which one of the iron atoms is replaced by aluminium and chrome-alumina-hisingerite variety in which chromium substitutes for iron.[3]


  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. ^ a b Handbook of Mineralogy
  3. ^ a b Mindat.org
  4. ^ a b Webmineral
  5. ^ Holtstam, Dan (2023-04-04). "Prehistory of an enigmatic mineral: hisingerite". GFF: 1–3. doi:10.1080/11035897.2023.2187079. ISSN 1103-5897.