carminite

{{Infobox mineral | name = Carminite | category = Arsenate minerals | boxwidth = 24 | boxbgcolor = | image = Carminite-170211.jpg | imagesize = 260px | caption = Carminite from the Alto das Quelhas do Gestoso Mines, Gestoso, Manhouce, São Pedro do Sul, Viseu District, Portugal. Picture width 1.5 mm. | formula = PbFe3+2(AsO4)2(OH)2 | IMAsymbol=Cmt | molweight = 639.87 g/mol | strunz = 8.BH.30 (10 ed) 7/B.28-40 (8 ed) | dana = 41 Anhydrous phosphates, arsenates and vanadates containing hydroxyl or halogen | system = Orthorhombic | class = Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) | symmetry = Cccm | unit cell = a = 16.591 Å, b = 7.58 Å, c = 12.285 Å; Z = 8 | colour = Carmine red | habit = Typically bladed crystals, also acicular crystals, in spherical or tufted aggregates and as fibrous or drusy masses | twinning = | cleavage = Distinct on {110} | fracture = | tenacity = Brittle (D, All) | mohs = | lustre = Vitreous, pearly on cleavages | refractive = nα = 2.070, nβ = 2.070, nγ = 2.080 | opticalprop = Biaxial (+) | birefringence = 0.010 | pleochroism = strong, X= pale yellowish red; Y=Z= dark carmine red | streak = Reddish yellow | gravity = 5.03–5.18 | melt = | fusibility = | diagnostic = | solubility = Slowly soluble in HCl with the separation of PbCl2, and totally soluble in HNO3 | diaphaneity =Translucent | other = Carminite is not radioactive. No piezoelectric effect could be detected | references = }}

thumb|alt=text|Carminite from the Alto das Quelhas do Gestoso Mines, Gestoso, Manhouce, São Pedro do Sul Municipality, Portugal|São Pedro do Sul, Viseu District, Portugal. Picture width 8 mm thumb|alt=text|Blue scorodite crystals on red brown carminite from Alto das Quelhas do Gestoso Mines, Gestoso, Manhouce, São Pedro do Sul, Viseu District, Portugal. Picture width 3 mm. Carminite (PbFe3+2(AsO4)2(OH)2) is an anhydrous arsenate mineral containing hydroxyl. It is a rare secondary mineral that is structurally related to palermoite (Li2SrAl4(PO4)4(OH)4). Sewardite (CaFe3+2(AsO4)2(OH)2) is an analogue of carminite, with calcium in sewardite in place of the lead in carminite. Mawbyite is a dimorph (same formula, different structure) of carminite; mawbyite is monoclinic and carminite is orthorhombic. It has a molar mass of 639.87 g. It was discovered in 1850 and named for the characteristic carmine colour.