Pyroxene

Pyroxenes are a major group of rock-forming silicate minerals built from single chains of silica tetrahedra. Their compositions commonly contain magnesium, iron, calcium, or combinations of these elements.

Silicate minerals: Minerals built from silicon–oxygen tetrahedra, alone or combined into larger structures. Pyroxene belongs to this broad mineral class because its structure is built from silica tetrahedra.
Single-chain silicate: A silicate structure formed by tetrahedra linked through shared oxygen atoms into one-dimensional chains. Pyroxene’s defining tetrahedral framework is a single chain.
Igneous petrology: The study of the origin, composition, and evolution of igneous rocks. Pyroxene compositions and textures help reconstruct magma crystallization.
Amphibole: A group of hydrous silicate minerals with double chains of silica tetrahedra and commonly elongated crystals. Its double chains and hydroxyl-bearing compositions contrast with pyroxene’s single chains and generally anhydrous structure.
Silica tetrahedron: A structural unit consisting of one silicon atom surrounded by four oxygen atoms. These units link into the single chains that define pyroxene structure.
Orthorhombic crystal system: A crystal system with three mutually perpendicular axes of unequal length. Many pyroxenes, including enstatite, crystallize in this symmetry.
Basalt: A fine-grained volcanic rock composed mainly of plagioclase and pyroxene, often with olivine. Pyroxene is a common major mineral in basalt.
Olivine: A magnesium- and iron-rich silicate mineral group built from isolated silica tetrahedra. Olivine lacks pyroxene’s linked tetrahedral chains.
Inosilicate: A silicate mineral with tetrahedra joined into chains, either single or double. Pyroxenes are single-chain inosilicates, distinguishing them from double-chain amphiboles.
Monoclinic crystal system: A crystal system with three unequal axes, two meeting at an oblique angle. Most calcium-rich clinopyroxenes crystallize in this symmetry.

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