a lithium aluminum silicate mineral (LiAlSi₂O₆) in the pyroxene family, an important ore of lithium and a source of ceramic materials. It is ordinarily found in lithium-bearing granite pegmatites. When brilliant and glassy, clear spodumene is valued as a semiprecious gem (more by collectors and museums than by the public, because its colour fades when it is exposed to sunlight). Its main varieties are hiddenite (emerald green) and kunzite (pink or lilac). The largest crystal of spodumene found is 14.3 metres (about 47 feet) long and 0.8 metre (about 3 feet) wide from the Etta mine in South Dakota, U.S.