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.

Bromargyrite
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
LusterAdamantine, resinous, waxy
StreakWhite to yellowish white
DiaphaneityTransparent, translucent
Specific gravity6.474
Optical propertiesIsotropic
Refractive indexn = 2.253
Birefringenceδ = 0.000
References[1][2][3]

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

edit
  1. ^ a b Mindat page for bromargyrite
  2. ^ Webmineral page for bromargyrite
  3. ^ a b Handbook of Mineralogy
  4. ^ a b "Definition of BROMYRITE". www.merriam-webster.com. Retrieved 2023-01-20.