vauquelinite

{{Infobox mineral | name = Vauquelinite | image = Vauquelinite-120513.jpg | imagesize = 260px | alt = | caption = | category = Phosphate mineral | formula = CuPb2(CrO4)(PO4)(OH) | IMAsymbol = Vql | molweight = | strunz = 7.FC.05 | system = Monoclinic | class = Prismatic (2/m) (same H-M symbol) | symmetry = P21/n | unit cell = a = 13.754(5) Å, b = 5.806(6) Å c = 9.563(3) Å; β = 94.55°; Z = 4 | color = Olive-green, apple-green, brown to nearly black | colour = | habit = Irregular wedge shaped crystals, mammillary, reniform masses | twinning = Present on {102} | cleavage = Indistinct | fracture = Irregular | tenacity = Brittle | mohs = 2.5 – 3 | luster = Adamantine, resinous | streak = Greenish or brownish | diaphaneity = Translucent | gravity = 6.16 | density = | polish = | opticalprop = Biaxial (−) | refractive = nα = 2.110 nβ = 2.220 nγ = 2.220 | birefringence = δ = 0.110 | pleochroism = X = Light green, Y = Light brown, Z = Light brown | 2V = Near zero | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = }}

Vauquelinite is a complex mineral with the formula CuPb2(CrO4)(PO4)(OH) making it a combined chromate and phosphate of copper and lead. It forms a series with the arsenate mineral fornacite.