Tusionite

Tusionite
General
Category Borate minerals
Formula
(repeating unit)		 MnSn(BO3)2
Strunz classification 6.AA.15
Crystal system Trigonal
Identification
Color Colorless, light yellow to yellow brown
Crystal habit Thin platy crystals in rosettes
Crystal symmetry Trigonal - rhombohedral
H-M symbol (3)
Cleavage [001] Perfect
Mohs scale hardness 5-6
Luster Vitreous
Streak white
Diaphaneity Translucent
Specific gravity 4.73
Optical properties Uniaxial (-)
Refractive index nω = 1.854 nε = 1.752
Birefringence δ = 0.102
References [1][2][3]

Tusionite is a rare colorless to transparent to translucent yellow brown trigonal borate mineral with chemical formula: MnSn(BO3)2. The mineral is composed of 18.86% manganese, 40.76% tin, 7.42% boron, and 32.96% oxygen. It is a late stage hydrothermal mineral and occurs rarely in granite pegmatites in miarolitic cavities.

Tusionite was named for the location where the mineral was first discovered and described in 1983 in the Tusion River Valley in the Pamir Mountains of Tajikistan. Tusionite has also been reported from Recice in the Czech Republic and in pegmatites at Thomas Mountain, Riverside County, California.

See also

References

  1. ↑ http://www.webmineral.com/data/Tusionite.shtml Webmineral data
  2. ↑ http://www.mindat.org/min-4062.html Mindat w/ location data
  3. ↑ http://rruff.geo.arizona.edu/doclib/hom/tusionite.pdf Mineral Handbook


This article is issued from Wikipedia - version of the Wednesday, March 30, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.