Svanbergite
Svanbergite with pyrophyllite and andalusite
General
CategoryPhosphate minerals
Formula
(repeating unit)
SrAl3(PO4)(SO4)(OH)6
IMA symbolSvb[1]
Strunz classification8.BL.05
Crystal systemTrigonal
Crystal classHexagonal scalenohedral (3m)
H-M symbol: (3 2/m)
Space groupR3m
Unit cella = 6.970–6.992 Å
c = 16.567–16.75 Å, Z = 3
Identification
ColorColorless, cream-yellow, rose, reddish brown
Crystal habitRhombohedral crystals (to pseudocubic); granular, massive
CleavageDistinct on {0001}
Mohs scale hardness5
LusterVitreous to adamantine
DiaphaneityTranslucent
Specific gravity3.22
Optical propertiesUniaxial (+)
Refractive indexnω = 1.631–1.635 nε= 1.646–1.649
Birefringenceδ=0.0140-0.0150
References[2][3]

Svanbergite is a colorless, yellow or reddish mineral with the chemical formula SrAl3(PO4)(SO4)(OH)6. It has rhombohedral crystals.[4]

It was first described for an occurrence in Varmland, Sweden in 1854 and named for Swedish chemist Lars Fredrik Svanberg (1805–1878).[2][3]

It occurs in high aluminium medium-grade metamorphic rocks; in bauxite deposits and from sulfate enriched argillic alteration ( high silica and clay) associated with hydrothermal systems often replacing apatite. It occurs with pyrophyllite, kyanite, andalusite, lazulite, augelite, alunite, kaolinite and quartz.[2]

Svanbergite crystals on white dolomite from Radium Hot Springs, British Columbia, Canada (size: 3 x 2.5 x 2.1 cm)

References

  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. 1 2 3 Mineral Handbook
  3. 1 2 Webmineral
  4. Richard V. Gaines, H. Catherine W. Skinner, Eugene E. Foord, Brian Mason, and Abraham Rosenzweig: "Dana's new mineralogy", p. 962. John Wiley & Sons, 1997


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