Chemistry:Bromargyrite

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Short description: Natural mineral form of silver bromide
Bromargyrite
Bromargyrit mit gediegen Silber - San Onofre, Mexiko.jpg
Bromargyrite with silver – San Onofre, Mexico.
General
CategoryHalide minerals
Formula
(repeating unit)
AgBr
Strunz classification3.AA.15
Crystal systemIsometric
Crystal classHexoctahedral (m3m)
H-M symbol (4/m 3 2/m)
Space groupFm3m
Unit cella = 5.7745 Å; Z = 4
Identification
ColorYellowish, greenish brown, bright green
CleavageNone observed
FractureIrregular/uneven, sub-conchoidal
TenacitySectile
Mohs scale hardness2 12
|re|er}}Adamantine, resinous, waxy
StreakWhite to yellowish white
DiaphaneityTransparent, translucent
Specific gravity6.474
Optical propertiesIsotropic
Refractive indexn = 2.253
Birefringenceδ = 0.000
References[1][2][3]

Bromyrite or bromargyrite[4] is a natural mineral form of silver bromide[4] found mainly in Mexico and Chile. Hardness is 1.5 to 2. Related are chlorargyrite and iodyrite.

It was first described in 1859 for an occurrence in Plateros, Zacatecas, Mexico where it occurred in a silver deposit as an oxidation product of primary ore minerals.[1] It occurs in arid environments along with native silver, iodargyrite and smithsonite along with iron and manganese oxide minerals.[3]

References