bismoclite

{{Infobox mineral | name = Bismoclite | image = Bismoclite (close-up).jpg | alt = | caption = Yellow-orange bismoclite interspersed with bismuthinite from the Alto do Giz pegmatite, Equador, Rio Grande do Norte, NE-region, Brazil. Approximate image width: 5 mm. | category = Halide mineral | formula = BiOCl | IMAsymbol=Bmc | molweight = | strunz = 3.DC.25 | dana = 10.2.1.2 | system = Tetragonal | class = Ditetragonal dipyramidal (4/mmm) H-M symbol: (4/m 2/m 2/m) | symmetry = P4/nmm | unit cell = a = 3.887 Å, c = 7.354 Å; Z = 2 | color = Cream-white, greyish, yellowish brown | colour = | habit = Platey to thin rectangular crystals, fibrous to columnar, massive | twinning = | cleavage = {001} perfect | fracture = | tenacity = Elastic | mohs = 2-2.5 | luster = Greasy, silky, pearly, dull, earthy | streak = White | diaphaneity = Transparent to translucent | gravity = 7.36 (measured), 7.784 (calculated) | density = | polish = | opticalprop = Uniaxial (-) | refractive = nω = 2.150 nε = 1.910 | birefringence = δ = 0.240 | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = }} Bismoclite is a bismuth oxohalide mineral with formula BiOCl. It is the naturally occurring form of bismuth oxychloride. The name was derived from its chemical constituents. It is a secondary bismuth mineral first thought to be composed of bismuthyl ions (BiO+) and chloride anions, however, the existence of the diatomic bismuthyl ion is doubtful.

It is a member of the matlockite group.