staurolite
staurolite A member of the nesosilicates and an important metamorphic index mineral with the approximate composition (Fe2+,Mg)2(Al,Fe3+)9O6[Si4O16](O,OH)2; sp. gr. 3.74–3.85; hardness 7.5; monoclinic; crystals prismatic; shades of brown; occurs in regionally metamorphosed schists and gneisses, such as iron-rich pelites, with a high Fe3+/Fe2+ ratio at moderate grades of metamorphism and in association with garnet (almandine) and kyanite; it may develop from chloritoid as the metamorphic grade increases.
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Hypersthene , hypersthene A member of the orthorhombic pyroxenes with approximately equal amounts of Fe and Mg in its composition MgFeSi2O6, it is a mineral occurr… Magnetite , magnetite (loadstone, lodestone) An important rock-forming iron oxide Fe2+Fe3+2O4 (FeO.Fe2O3) and member of the spinel group of minerals; belongs to… Siouan , Siouan •Brian, cyan, Gaian, Geminian, Hawaiian, ion, iron, Ixion, lion, Lyon, Mayan, Narayan, O'Brien, Orion, Paraguayan, prion, Ryan, scion, Uruguay… Leucite , leucite An important feldspathoid mineral KA1Si2O6; sp.gr.2.5; hardness 5.5–6.0; tetragonal; normally white or grey; vitreous lustre; crystals form v… Rutile , rutile
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staurolite