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SPODUMENE
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Spodumene is the only one of the gem minerals except tourmaline and lepidolite, which contains the element lithium in any large amount. It is a silicate of alumina and lithia, having the percentages, silica 64.5, alumina 27.4, and lithia 8.4. It fuses rather easily before the blowpipe, and gives the purple-red color of lithia to the flame, making a convenient means of distinguishing the species. Its hardness is 6.5-7, and specific gravity 3.1-3.2. Its luster is vitreous. Ordinarily it is opaque, and of a white or gray color, the word spodumene being derived from the Greek spodios, meaning ash-colored.
Spodumene crystallizes in the monoclinic system, often forming large crystals up to four feet in length. The use of spodumene as a gem is confined almost exclusively to a transparent emerald-green variety occurring in North Carolina, and a yellow variety, also transparent, obtained in Brazil. The emerald-green spodumene is known as hidden-ite, after W. E. Hidden, who first developed it. It occurs in thin, bladed crystal's, varying from colorless through yellow to an emerald-green color. These afford only small gems, none over five carats being obtainable. A high price has been obtained for these, ranging between forty dollars and one hundred dollars per carat. They are cut into step or table stones, as this best exhibits their dichroism, and avoids the danger of splitting from the marked prismatic cleavage present. All the hiddenite thus far known has been obtained at Stony Point, Alexander County, North Carolina, and this locality is now exhausted.
The yellow spodumene, above referred to as obtained in Brazil, was long thought to be chrysoberyl. Its distinction from chrysoberyl, by the properties above mentioned, is easy, although its use in jewelry is similar. Pieces of spodumene, of a beautiful blue color, are also occasionally found near Diamantina, in Brazil. Quite recently spodumene has been found near Pala, San Diego County, California, in the form of large transparent crystals of an amethystine hue. These afford large, handsome gems, resembling amethyst in color, but distinguished from it by their dichroism and their rose to lilac shades. The name of kunzite has been applied to this variety of spodumene.
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