Spodumene is a pyroxene consisting of lithium, Li 3)2, and is a source of lithium. It occurs as colorless to yellowish, purplish, or lilac kunzite (see below), yellowish-green or emerald-green hiddenite , prismatic crystals, often of great size. Single crystals of 14.3 m (47 ft) in size are reported from the Black Hills , United States
The naturally occurring low-temperature form α-spodumene is in the monoclinic system whereas the high-temperature β-spodumene crystallizes in the tetragonal system. α-spodumene converts to β-spodumene at temperatures above 900 °C. Crystals are typically heavily striated parallel to the principal axis. Crystal faces are often etched and pitted with triangular markings.