Svanbergite , Uvite Locality: Brumado, Bahia, Brazil Size: miniature, 6 x 3 x 3 cm Svanbergite on Uvite Tourmaline A very fine and unusually attractive display specimen of svanbergite crystals to 6mm on matrix of contrasting green uvite. The Svanbergite is large and well-formed, and the perch on uvite is unusual. ex. Carlos Barbosa — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Svanbergite
A strontium-aluminium phosphate-sulfate of the alunite group, described in 1854 from Sweden.
Intro adapted from Wikipedia (CC BY-SA).
Svanbergite is an IMA-recognized mineral species in the phosphate class, with the chemical formula SrAl₃(SO₄)(PO₄)(OH)₆.
It crystallizes in the trigonal crystal system (space group R-3m). It is a member of the Alunite-beudantite structural group.
Key properties: Mohs hardness 5; specific gravity 3.2–3.24; Vitreous to adamantine luster; refractive index 1.64; optically uniaxial.
IMA symbol Svb, IMA status: approved, named in 1854.
Found in aluminous medium-grade metamorphic deposits; from bauxite deposits; a product of sulphatic argillic wall-rock alteration in hydrothermal vein and disseminated ore deposits, replacing apatite.
It is found associated with Pyrophyllite, kyanite, andalusite, lazulite, augelite, alunite, kaolinite, quartz.
The mineral was named to honor Lars Fredrik Svanberg (1805–1878), Swedish chemist, Professor of Mineralogy, University of Uppsala, Uppsala, Sweden.