Bromargyrite

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
Category	Halide minerals
Formula	AgBr
Strunz classification	3.AA.15
Crystal system	Isometric
Crystal class	Hexoctahedral (m3m) H-M symbol (4/m 3 2/m)
Space group	Fm3m
Unit cell	a = 5.7745 Å; Z = 4
Identification
Color	Yellowish, greenish brown, bright green
Cleavage	None observed
Fracture	Irregular/uneven, sub-conchoidal
Tenacity	Sectile
Mohs scale hardness	2+1⁄2
Luster	Adamantine, resinous, waxy
Streak	White to yellowish white
Diaphaneity	Transparent, translucent
Specific gravity	6.474
Optical properties	Isotropic
Refractive index	n = 2.253
Birefringence	δ = 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]