Brewsterite-Sr Locality: Whitesmith Mine, Strontian, Scottish Highlands, United Kingdom Description: Colorless to pearly white shiny, pseudocube crystals. Camer — Photo: HolDu · CC BY-SA 3.0 de
Brewsterite-Sr
Also known as: Brewsterite.
Brewsterite is the name of a series of tectosilicate minerals of the zeolite group. Prior to 1997, brewsterite was recognized as a mineral species, but a reclassification in 1997 by the International Mineralogical Association changed it to a series name, with the mineral species being named brewsterite-Sr and brewsterite-Ba. Brewsterite-Sr, the more common of these, is a hydrous strontium and aluminium silicate, (Sr,Ba)2Al4Si12O32·10H2O. Small amounts of barium is usually present replacing part of the strontium. The appropriate species name depends on the dominant element.
Intro adapted from Wikipedia (CC BY-SA).
Brewsterite-Sr is an IMA-recognized mineral species in the silicate class, with the chemical formula Sr(Al₂Si₆)O₁₆·5H₂O.
It crystallizes in the monoclinic crystal system (space group P-1). It is a member of the Brewsterite structural group.
Key properties: Mohs hardness 4.5; specific gravity 2.45; typically white or colorless or yellow or gray; White streak; Vitreous to pearly on {010} luster; optically biaxial.
IMA symbol Brw-Sr, IMA status: approved, named in 1822.
Hydrothermally deposited in druses lining cavities in basalts and schists; more rarely in ore deposits.
It is found associated with Zeolites, calcite, quartz.
The mineral was named to honor Sir David Brewster (1781–1868), Scottish mineralogist.
Collections: Collector Favorites, Rare & Remarkable.