threepyroxene

Threepyroxene is a hypothetical inosilicate mineral proposed to consist of three interlinked pyroxene-like chains within a single crystal structure. The concept envisions a higher-order polymerization of silicate tetrahedra than found in ordinary pyroxenes, potentially yielding distinct crystallographic, optical, and mechanical properties. As a theoretical construct, threepyroxene has not been documented as a naturally occurring mineral and has no formal recognition in mineral catalogs.

In proposed models, the threepyroxene framework would extend along a crystallographic direction with three repeat silicate units connected in a triple-chain arrangement. Cation sites typical of pyroxenes, designated as X and Y in the general XYSi2O6 framework, would accommodate common substituents such as calcium, magnesium, iron, and sodium, suggesting possible solid-solution behavior analogous to other pyroxenes. The triple-chain topology could influence cleavage tendencies, fracture behavior, and refractive properties in ways that differ from conventional single-chain pyroxenes.

Occurrence and research status are limited to theoretical discussions and exploratory laboratory work. No confirmed natural specimens exist, and no IMA-listed mineral species has been named threepyroxene. If pursued in synthesis, such a phase would require silicate-formation conditions at high temperature and specific pressure regimes that stabilize extended chain structures. Scientists studying threepyroxene typically examine its potential implications for understanding silicate polymerization, mineral stability in extreme environments, and the boundaries of pyroxene chemistry.

See also: pyroxene, inosilicate, chain silicate, mineral theory.