Chemistry:Fluororichterite

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Fluororichterite
Fluororichterite-Calcite-280570.jpg
Fluororichterite with calcite from Wilberforce, Monmouth Township, Haliburton County, Ontario, Canada (size: 6.6 x 4.4 x 3.8 cm)
General
CategorySilicate mineral
Formula
(repeating unit)
Na(NaCa)Mg5Si8O22F2
Strunz classification9.DE.20
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupC2/m
Unit cella = 9.763, b = 17.89
c = 5.122 [Å]; β = 102.25°; Z = 2
Identification
ColorBrown to brownish-red, rose-red, yellow, grey-brown, also pale to dark green
Mohs scale hardness5 - 6
|re|er}}Vitreous
StreakWhite
Specific gravity3.17
References[1][2][3]

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

Occurrence

Fluororichterite was first reported from the Ilmen Nature 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