ferrimolybdite

{{infobox mineral | name = Ferrimolybdite | image = Ferrimolybdite-154908.jpg | alt = | caption = Ferrimolybdite crystals from the Kingman District, Mohave County, Arizona | category = Molybdate mineral | formula = Fe3+2(MoO4)3·8(H2O) or Fe3+2(MoO4)3·n(H2O) | IMAsymbol = Fmyb | molweight = | strunz = 7.GB.30 | dana = | system = Orthorhombic | class = Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) | symmetry = Pmmn | unit cell = a = 6.665, b = 15.423 c = 29.901 [Å]; Z = 8 | color = Canary-yellow, straw-yellow, greenish yellow | habit = Acicular tufted to radial aggregates; powdery, earthy | twinning = | cleavage = Distinct on {001} | fracture = Uneven | tenacity = | mohs = 1-2 | luster = Adamantine, silky, earthy | streak = Light yellow | diaphaneity = Transparent to translucent | gravity = 2.99 | density = | polish = | opticalprop = Biaxial (+) | refractive = nα = 1.720 - 1.810 nβ = 1.730 - 1.830 nγ = 1.850 - 2.040 | birefringence = δ = 0.130 - 0.230 | pleochroism = X = Y = clear to nearly colorless; Z = dirty gray to canary-yellow | 2V = 26° to 32° (calculated) | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = }} Ferrimolybdite is a hydrous iron molybdate mineral with formula: Fe3+2(MoO4)3·8(H2O) or Fe3+2(MoO4)3·n(H2O). It forms coatings and radial aggregates of soft yellow needles which crystallize in the orthorhombic system.

==Discovery and occurrence== It was first described in 1914 for an occurrence in the Alekseevskii Mine in the Karysh River Basin, Khakassia Republic, Siberia, Russia. It was named for its composition (ferric iron and molybdenum).