Svanbergite

Svanbergite

Svanbergite with pyrophyllite and andalusite
General
Category Phosphate minerals
Formula
(repeating unit)		 SrAl3(PO4)(SO4)(OH)6
Strunz classification 08.BL.05
Crystal symmetry Trigonal hexagonal scalenohedral
H-M symbol: (32/m)
Space group: R 3m
Unit cell a = 6.970–6.992 Å, c = 16.567–16.75 Å, Z = 3
Identification
Color Colorless, cream-yellow, rose, reddish brown
Crystal habit Rhombohedral crystals (to pseudocubic); granular, massive
Crystal system Trigonal
Cleavage Distinct on {0001}
Mohs scale hardness 5
Luster Vitreous to adamantine
Diaphaneity Translucent
Specific gravity 3.22
Optical properties Uniaxial (+)
Refractive index nω = 1.631–1.635 nε= 1.646–1.649
Birefringence δ=0.0140-0.0150
References [1][2]

Svanbergite is a colorless, yellow or reddish mineral with the chemical formula SrAl3(PO4)(SO4)(OH)6. It has rhombohedral crystals.[3]

It was first described for an occurrence in Varmland, Sweden in 1854 and named for Swedish chemist Lars Fredrik Svanberg (1805–1878).[1][2]

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.[1]

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

References

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  1. 1 2 3 Mineral Handbook
  2. 1 2 Webmineral
  3. ↑ 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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