Enstatite

Enstatite is a magnesium-rich pyroxene mineral with the formula MgSiO₃. It occurs in igneous and metamorphic rocks and in some meteorites.

Pyroxene: Pyroxenes are a major group of inosilicate minerals built from single chains of silicate tetrahedra. Enstatite is the magnesium end-member of the orthopyroxene subgroup within this mineral family.
Polymorphism: The ability of a solid chemical composition to crystallize in more than one structure. MgSiO₃ adopts several structures, including enstatite, depending on conditions.
Peridotite: A coarse-grained igneous rock composed mainly of olivine and pyroxene. Enstatite is a common orthopyroxene in many peridotites from Earth’s mantle.
Ferrosilite: An iron-rich orthopyroxene with the ideal formula Fe₂Si₂O₆. Ferrosilite is the iron-rich counterpart to enstatite in the orthopyroxene series.
Orthopyroxene: Orthopyroxenes are pyroxene minerals with orthorhombic crystal symmetry and compositions dominated by magnesium and iron. Enstatite belongs to this subgroup, whose structure distinguishes it from clinopyroxenes.
Protoenstatite: A high-temperature orthorhombic polymorph of magnesium metasilicate. Heating can transform enstatite into this distinct MgSiO₃ structure.
Chondrite: A stony meteorite containing rounded chondrules and material that has not undergone extensive melting. Enstatite occurs in chondrites, where its chemistry records conditions in the early Solar System.
Diopside: A calcium-magnesium clinopyroxene with the ideal formula CaMgSi₂O₆. Unlike enstatite, diopside is calcium-bearing and has monoclinic crystal symmetry.
Enstatite–ferrosilite series: A mineral series in which magnesium and iron substitute for one another in orthopyroxene compositions. Enstatite forms the magnesium-rich end of the series, opposite iron-rich ferrosilite.
Clinoenstatite: A monoclinic polymorph of magnesium metasilicate, MgSiO₃. Enstatite can transform to this structure under particular temperature and pressure conditions.

Linked from 3 pages