zussmanite

{{Infobox mineral | name = Zussmanite | image = | alt = | caption = | category = Phyllosilicate minerals | formula = | molweight = |IMAsymbol=Zus| strunz = 9.EG.35 | system = Trigonal | class = Pyramidal (3) H-M symbol: (3) | symmetry = R3 | unit cell = a = 11.66, c = 28.69 [Å]; Z = 3 | color = Light to medium green | colour = | habit = Tabular crystals | twinning = | cleavage = Perfect {0001} | fracture = Micaceous | tenacity = Flexible | mohs = | luster = Sub-vitreous, resinous, greasy | streak = White | diaphaneity = Translucent | gravity = 3.146 | density = | polish = | opticalprop = Uniaxial (−) | refractive = nω = 1.643 nε = 1.623 | birefringence = δ = 0.020 | pleochroism = Weak; O = pale green; E = colorless | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = }}

Zussmanite is a hydrated iron-rich silicate mineral with the chemical formula . It occurs as pale green crystals with perfect cleavage.