anandite

{{infobox mineral | name = Anandite | image = | alt = | caption = | category = Phyllosilicate minerals | group = Mica group, brittle mica group | formula = {{chem2|(Ba,K)(Fe^{2+},Mg)3(Si,Al,Fe)4O10(S,OH)2}} |IMAsymbol=Ana | molweight = | strunz = 9.EC.35 | dana = | system = Monoclinic | class = Prismatic (2/m) (same H-M symbol) | symmetry = C2/m | unit cell = a = 5.412(5), b = 9.434(5) c = 19.953(10) [Å]; β = 95°; Z = 2 | color = Black | colour = | habit = Massive, prismatic crystals poorly formed produce hexagonal outline cleavage fragments | twinning = | cleavage = Perfect on {001} | fracture = Flexible fragments | tenacity = | mohs = 3 – 4 | luster = Vitreous | streak = Grey white | diaphaneity = Nearly opaque | gravity = 3.94 | density = | polish = | opticalprop = Biaxial (+) | refractive = nα = 1.855 nγ = 1.880 | birefringence = | pleochroism = Y = green; Z = brown | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = }} Anandite is a rare phyllosilicate with formula {{chem2|(Ba,K)(Fe^{2+},Mg)3(Si,Al,Fe)4O10(S,OH)2}}. It crystallizes in the monoclinic crystal system. It is black in color with a glassy luster and a near perfect cleavage.

It was first described in 1967 for an occurrence in the Wilagedera Prospect of the North Western Province of Sri Lanka in bands of iron ore. It has also been found in Big Creek in Fresno County and in Trumball Peak in Mariposa County, California as well as the Sterling Mine in New Jersey. It was named for Ananda Kentish Coomaraswamy (1877–1947), who was the first director of the Mineral Survey of Ceylon, Sri Lanka.