hydrozincite

{{Infobox mineral | name = Hydrozincite | boxwidth = | boxbgcolor = | image = Hydrozincite-Smithsonite-210865.jpg | imagesize = 260px | alt = | caption = | category = Carbonate mineral | formula = Zn5(CO3)2(OH)6 | IMAsymbol = Hznc | molweight = | strunz = 5.BA.15 | dana = | system = Monoclinic | class = Prismatic (2/m) (same H-M symbol) | symmetry = C2/m | unit cell = a = 13.58 Å, b = 6.28 Å, c = 5.41 Å; β = 95.51°, Z = 2 | color = White to grey, stained pale pink, or pale yellow or brown; colourless in transmitted light. | colour = | habit = Lathlike or bladed crystals uncommon, in fibrous, stalactitic, reniform, pisolitic aggregates; also earthy, chalky, massive | twinning = Contact twinning on {100} | cleavage = Perfect on {100} | fracture = Irregular/uneven | tenacity = Very brittle | mohs = 2– | luster = Silky, pearly, dull, earthy | streak = White | diaphaneity = Transparent, translucent | gravity = 3.5–4 | density = | polish = | opticalprop = Biaxial (−) | refractive = nα = 1.630 nβ = 1.642 nγ = 1.750 | birefringence = δ = 0.120 | pleochroism = | 2V = Measured: 40°, calculated: 40° | dispersion = relatively strong | extinction = | length fast/slow = | fluorescence = Fluoresces pale blue to lilac under UV | absorption = | melt = | fusibility = | diagnostic = | solubility = Readily soluble in acids. | impurities = | alteration = | other = | prop1 = | prop1text = | references = }}

Hydrozincite, also known as zinc bloom or marionite, is a white carbonate mineral consisting of Zn5(CO3)2(OH)6. It is usually found in massive rather than crystalline form.