Al SiO. A metamorphic mineral formed by the recrystallization of clay minerals at moderate to high pressures and temperatures.
An aluminum-rich silicate found only in metamorphic rocks that form at high temperature and pressure.
A mineral, consisting of alumina and silica.
A silicate of aluminium, Al2 SiO5, common in aluminous rocks of high metamorphic grade.
Sillimanite (aluminum silicate, Al2 SiO5) is a transparent to translucent mineral that ranges in color from white to gray to brownish to greenish. Sillimanite has the same chemical formula as both kyanite and andalusite (these three minerals are polymorphs); Sillimanite is the rarest of the three (all three are used in high-temperature ceramics, used in spark plugs). Sillimanite has a hardness of 7.5 and a specific gravity of 3.2. Sillimanite is the state mineral of Delaware (since March 24, 1977); SIllimanite is found near near Wilmington, Delaware. Sillimanite is found in Brazil, New England (USA), and Europe; it is found in areas of high-grade metamorphic rock.
a silicate of aluminum occurring in orthorhombic crystals, trimophous with andalusite and kyanite. [AHDOS
Sillimanite also called Bucholzite is an alumino-silicate mineral with the chemical formula Al2SiO5. Sillimanite is named after the American chemist Benjamin Silliman (1779-1864).