SPODUMENE, a *lithium-aluminium silicate belonging to the pyroxene group (see PYROXENE), named in 1800 from Gr. airobtos (ash-coloured), in allusion to its colour, and soon afterwards termed by J. R. Haily triphane (r ptct.avis, ap pearing three-fold), because it exhibited certain characteristics equally in three directions. Spodumene crystallizes in the mono clinic system, the crystals having generally a prismatic habit and being of ten striated longitudinally. It has perfect prismatic cleav age, and imperfect cleavage parallel to the clinopinacoid, whilst a lamellar structure may be developed by parting along the ortho pinacoid. The hardness is 6.5 to 7, and the sp.gr. about 3.16. Though generally a dull mineral, some varieties of spodumene are so brightly coloured and transparent as to be valued as gem-stones, e.g., the emerald-green hiddenite (q.v.) and the lilac-coloured kunzite (q.v.), whilst a yellow or yellowish-green spodumene
found as pebbles in the state of Minas Geraes, Brazil, resembles, when cut, some kinds of chrysoberyl. Common spodumene is used as a source of lithium in chemical preparations.
Spodumene occurs in granite and crystalline schists. The orig inal specimens came from the isle of Uto, Sweden, but the finest examples are found in the United States, especially in Massachu setts, fine specimens having also been obtained from the Black. Hills of S. Dakota. Some remarkable deposits containing spodu mene were discovered many years ago at Branchville, Connecticut, and were exhaustively studied by G. J. Brush and E. S. Dana. The spodumene occurred in large quantity, in a vein of albite granite, associated with apatite, garnet, columbite, pitchblende and other uranium minerals, with several manganese phosphates.