Hiddenite / Spodumene or Kunzite "eyes" pendant from Afghanistan

Spodumene is a pyroxene mineral consisting of lithium aluminium inosilicate, LiAl(SiO3)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 of South Dakota, United States. The normal low-temperature form α-spodumene is in the monoclinic system whereas the high-temperature β-spodumene crystallizes in the tetragonal system. The normal 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. Spodumene was first described in 1800 for an occurrence in the type locality in Utö, Södermanland, Sweden. It was discovered by Brazilian naturalist Jose Bonifacio de Andrada e Silva. The name is derived from the Greek spodumenos (σποδυμενος), meaning "burnt to ashes," owing to the opaque, ash-grey appearance of material refined for use in industry. Spodumene occurs in lithium-rich granite pegmatites and aplites. Associated minerals include: quartz, albite, petalite, eucryptite, lepidolite and bery;. Transparent material has long been used as a gemstone with varieties kunzite and hiddenite noted for their strong pleochroism. Source localities include Afghanistan, Australia, Brazil, Madagascar, Pakistan, Québec in Canada and North Carolina, California in the US.