messelite

{{Infobox mineral | name = Messelite | category = Phosphate mineral | boxwidth = | boxbgcolor = | image = Messelite-546647.jpg | imagesize = | caption = Messelite from Germany | formula = Ca2(Fe2+,Mn2+)(PO4)2·2H2O | IMAsymbol = Msl | molweight = | strunz = 8.CG.05 | dana = 40.2.2.2 | system = Triclinic | class = Pinacoidal () (same H-M symbol) | symmetry = P | unit cell = a = 5.8 Å, b = 6.6 Å, c = 5.5 Å α = 102°, β = 109°, γ = 90°; Z = 1 | color = White, pale greenish white, greenish gray, pink, colorless | habit = | twinning = | cleavage = Perfect on {001}, producing curved irregular surfaces | fracture = Uneven | tenacity = | mohs = 3.5 | luster = | polish = | refractive = nα = 1.644nβ = 1.653nγ = 1.680 | opticalprop = Biaxial (+) | birefringence = δ = 0.036 | 2V = 20° to 35° (measured) | dispersion = Relatively strong | pleochroism = | fluorescence= | absorption = | streak = | gravity = 3.16 | density = | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = Translucent | other = | references = }} Messelite is a mineral with formula Ca2(Fe2+,Mn2+)(PO4)2·2H2O. It was discovered in Germany and described in 1890. The mineral was subsequently discredited in 1940, reinstated and named neomesselite in 1955, and the name restored to messelite in 1959.

==Description== Messelite is a translucent mineral that is white, pale greenish white, greenish gray, pink, or colorless. The mineral may be granular or occur as internally radial aggregates of lamellar crystals arranged as globes, hemispheres, or sheafs, up to .