danalite

{{infobox mineral | name = Danalite | category = Tectosilicate minerals | group = Feldspathoid group | boxwidth = | boxbgcolor = | image = Danalite-202027.jpg | imagesize = | alt = | caption = | formula = Fe2+4Be3(SiO4)3S | IMAsymbol = Dan | molweight = | strunz = 9.FB.10 | dana = 76.02.04.02 | system = Isometric | class = Hextetrahedral (3m) H-M symbol: ( 3m) | symmetry = P3n | color = Yellow, pink, reddish brown, red: colorless to pink in thin section | colour = | habit = Octahedral and dodecahedral crystals, typically massive or as segregations | twinning = | cleavage = {111} and {11} | fracture = Subconchoidal to uneven | tenacity = Brittle | mohs = 5.5 to 6 | luster = Vitreous or greasy | streak = Grey white | diaphaneity = Semitransparent | gravity = 3.28 – 3.46 | density = | polish = | opticalprop = Isotropic | refractive = n = 1.747 – 1.771 | birefringence = | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence= | absorption = | melt = | fusibility = | diagnostic = | solubility = | other = | alteration = | references = }} Danalite is an iron beryllium silicate sulfide mineral with formula: Fe2+4Be3(SiO4)3S.

It is a rare mineral which occurs in granites, tin bearing pegmatites, contact metamorphic skarns, gneisses and in hydrothermal deposits. It occurs in association with magnetite, garnet, fluorite, albite, cassiterite, pyrite, muscovite, arsenopyrite, quartz, and chlorite.