serpierite

{{Infobox mineral | name = Serpierite | category = Sulfate mineral | boxwidth = 24 | boxbgcolor = | image = Serpierite-105024.jpg | imagesize = 260px | caption = Serpierite from the Genna zinc smelter, Germany (slag locality) | formula = | IMAsymbol = Spe | molweight = 644.32 g/mol | strunz = 7.DD.30 (10 ed.) VI/D.19-20 (8 ed.) | dana = 31.06.02.01 | system = Monoclinic | class = Prismatic (2/m) (same H-M symbol) | symmetry = B2/b | colour = Sky blue | habit = Crusts and tufted aggregates of tiny lathlike crystals | twinning = | cleavage = Perfect on {001} | fracture = Splintery | tenacity = Brittle | mohs = | lustre = Vitreous, pearly on cleavages | refractive = nα = 1.58, nβ = 1.64, nγ = 1.65 | opticalprop = Biaxial (−) | birefringence = 0.065, 0.0640 | pleochroism = X = pale green; Y = bluish green; Z = bluish green | streak = White, pale blue or greenish white | gravity = 3.07 | melt = | fusibility = | diagnostic = | solubility = Soluble in acids | diaphaneity = Transparent | other = Serpierite is not radioactive | references = }}

Serpierite () is a rare, sky-blue coloured hydrated sulfate mineral, often found as a post-mining product. It is a member of the devilline group, which has members aldridgeite , campigliaite , devilline , kobyashevite , lautenthalite and an unnamed dimorph of devilline. It is the calcium analogue of aldridgeite and it is dimorphous with orthoserpierite .