Fluoro-richterite

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
IMA symbol	Flrct[1]
Strunz classification	9.DE.20
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	C2/m
Unit cell	a = 9.763, b = 17.89 c = 5.122 [Å]; β = 102.25°; Z = 2
Identification
Color	Brown to brownish-red, rose-red, yellow, grey-brown, also pale to dark green
Mohs scale hardness	5 - 6
Luster	Vitreous
Streak	White
Specific gravity	3.17
References	[2][3][4]

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

Occurrence[]

Fluororichterite was first reported from the Ilmen Nature Reserve, , 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.^[2]

At the type locality in the Ilmen Mountains fluororichterite occurs in carbonate veins in amphibolites and ultramafic rocks.^[5] In the Essonville occurrence in Wilberforce, Ontario it occurs in a limestone lens within a gneiss and is associated with phlogopite and calcite.^[6] It has also been reported from Austria, Germany, Italy, Spain and China.^[2] At Coyote Peak in the Coastal Range, Humboldt County, California, it occurs with a variety of rare minerals in an alkaline mafic diatreme.^[7]

References[]