Svanbergite

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Svanbergite
Svanbergite w-pyrophyllite on andalusite Basic strontium aluminum phosphate Donally Mine near Thorne Minerals County Nevada 1879.jpg
Svanbergite with pyrophyllite and andalusite
General
Category Phosphate minerals
Formula
(repeating unit)
SrAl3(PO4)(SO4)(OH)6
Strunz classification 8.BL.05
Crystal system Trigonal
Crystal class Hexagonal scalenohedral (3m)
H-M symbol: (3 2/m)
Space group R3m
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
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[edit]


  1. ^ a b c Mineral Handbook
  2. ^ a b 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