The name pyroxene translates directly to fire stranger, a label bestowed by eighteenth-century geologists who mistakenly believed these crystals were unwanted intruders trapped within volcanic glass. This misconception arose because early observers found these hard, dark crystals embedded in the black, glassy matrix of cooled lava flows, assuming they were impurities that had somehow survived the fiery eruption.
The internal architecture of pyroxene is defined by parallel chains of silica tetrahedra that resemble steel I-beams interlocked in a precise geometric pattern. Each silicon ion sits at the center of a tetrahedron surrounded by four oxygen ions, sharing two of those oxygen atoms with neighboring silicon ions to form a continuous single chain.
The International Mineralogical Association currently recognizes twenty mineral names, while discarding one hundred and five previously used terms, reflecting the dynamic nature of mineral classification. A typical pyroxene contains silicon in the tetrahedral site and predominantly divalent ions like magnesium, iron, or calcium in the X and Y sites, yielding an approximate formula of XY(Si,Al)2O6.
The upper mantle of Earth is composed mainly of olivine and pyroxene minerals, making these crystals the most abundant single-chain silicate minerals on the planet. A sample of pyroxenite from the Martian meteorite ALH84001 confirms that pyroxene minerals are a dominant component of the Martian crust, providing a window into the geological history of the Red Planet.
Jadeite is a sodium-rich pyroxene with the chemical formula NaAlSi2O6 that was once thought to be a variety of nephrite jade. This mineral is often found in metamorphic rocks formed under high pressure and low temperature conditions, such as those found in the Himalayas and the Andes.