Fluororichterite

Fluororichterite

Fluororichterite with calcite from Wilberforce, Monmouth Township, Haliburton County, Ontario, Canada (size: 6.6 x 4.4 x 3.8 cm)
General
Category Silicate mineral
Formula
(repeating unit)
Na(NaCa)Mg5Si8O22F2
Strunz classification 09.DE.20
Crystal system Monoclinic
Unit cell a = 9.763 Å, b = 17.89 Å, c = 5.122 Å; β = 102.25°
Identification
Color Brown to brownish-red, rose-red, yellow, grey-brown, also pale to dark green
Crystal symmetry Monoclinic prismatic
H-M symbol: (2/m)
Space group: C 2/m
Mohs scale hardness 5 - 6
Luster Vitreous
Streak White
Specific gravity 3.17
References [1][2][3]

Fluororichterite is a rare amphibole with formula Na(NaCa)Mg5Si8O22F2.

Occurrence

Fluororichterite was first reported from the Ilmen Natural Reserve, Ilmen Mountains, Chelyabinsk Oblast', Southern Urals, Russia. It was recognized by the International Mineralogical Association in 1994. Its name is derived from its fluorine content and relation to richterite.[1]

At the type locality in the Ilmen Mountains fluororichterite occurs in carbonate veins in amphibolites and ultramafic rocks.[4] In the Essonville occurrence in Wilberforce, Ontario it occurs in a limestone lens within a gneiss and is associated with phlogopite and calcite.[5] It has also been reported from Austria, Germany, Italy, Spain and China.[1] At Coyote Peak in the Coastal Range, Humboldt County, California, it occurs with a variety of rare minerals in an alkaline mafic diatreme.[6]

References

This article is issued from Wikipedia - version of the Sunday, March 06, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.