LiAlSi2O6

LiAlSi2O6, commonly known as spodumene, is a lithium aluminum silicate mineral that belongs to the pyroxene group of inosilicates. Its chemical formula is LiAlSi2O6. Spodumene crystallizes in the monoclinic system and forms elongated prismatic crystals that are transparent to translucent and have a vitreous luster. Pure material is colorless, but trace elements produce a wide range of colors; pink variety is called kunzite, green variety is hiddenite, while other hues occur in crystals that are yellow to lavender. The mineral is a principal source of lithium worldwide.

Spodumene forms in lithium-rich granitic pegmatites and, less commonly, in other igneous and metamorphic rocks. It is commonly found with quartz, feldspar, and mica, and occurs in relatively coarse-grained aggregates in pegmatites. Economic deposits are mined for lithium ore.

Mohs hardness about 6.5–7, specific gravity around 3.1–3.2, cleavage is imperfect in two directions that typically intersect near 90 degrees. It has pleochroism and is commonly cut as a gemstone when transparent, especially the kunzite and hiddenite varieties. It exhibits a vitreous luster and typically forms elongated crystals.

The mineral is the principal lithium ore; after processing to concentrate Li2O, lithium is used in batteries, ceramics, glass, and various chemical applications. Spodumene crystals are also valued as gemstones in some varieties. The name spodumene derives from Greek spodos meaning ash, referring to the dull, ash-like coloration of some specimens.