Spodumene - Encyclopedia

    Class : Silicates
    Subclass : Inosilicates
    Crystal system : Monoclinic
    Chemistry : LiAlSi₂O₆
    Rarity : Uncommon

Spodumene is the pyroxene of sodium and lithium pegmatites (sodolithic pegmatites). It has two particularly rare gemstone varieties : very pale green hiddenite (linked to traces of chromium) and pale pink kunzite (linked to traces of manganese). It owes its name to the Greek spodios (ashy) in allusion to the color of the mineral when heated. The crystals are generally elongated and flattened prismatic, with striated faces parallel to the elongation, commonly twinned ; spodumene also occurs in compact cryptocrystalline masses. Of vitreous luster, with a perfect cleavage according to (110), its color is variable, white, grayish, greenish. The transparent gemmy varieties are lilac pink (kunzite variety) or much rarer green to emerald green (hiddenite variety). Spodumene is an important ore of lithium, a light metal that finds applications in the manufacture of lubricants, as a flux in the aluminum industry, in ceramics, batteries as well as air conditioning. Varieties of gems, pale pink kunzite and green hiddenite were used in jewelry.

In France, spodumene is reported as microcrystals in the Gwernavalou quarry near Guingamp (Côtes-d'Armor).

Spodumene commonly twins on (100).

No false recorded for this mineral species. In contrast, gemmy varieties are commonly treated to produce yellow to green tints. Irradiation of spodumene produces an orange to yellow-greenish color, these colors have not been described in Nature to date. When a kunzite is irradiated it produces an unstable light green to intense green hue (picture on the right) which fades when exposed to sunlight or gentle heating. The establishment of the systematic irradiation of American mail to counter attacks using envelopes contaminated with anthrax after the attacks of September 11, 2001 led to the involuntary color change of many kunzites passing through the postal service.