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Spodumene



"Kunzite" redirects here. For the Sailor Moon character, see Shitennou.
Spodumene

An almost colorless kunzite crystal (upper left), a cut pale pink kunzite (upper right) and a greenish hiddenite crystal (below) (unknown scale)
General
CategoryMineral
Chemical formulalithium aluminium silicate, LiAl(SiO3)2
Identification
ColorHighly variable: white, colorless, gray, pink, lilac, violet, yellow and green
Crystal habitprismatic, generally flattened and elongated
Crystal systemmonoclinic; 2/m
CleavagePerfect prismatic, two directions at nearly 90°
FractureSub-conchoidal
Mohs Scale hardness6.5 - 7
LusterVitreous
Refractive index1.66-1.68
PleochroismStrong in kunzite: pink, colorless; hiddenite: yellow-green, blue-green
Streakwhite
Specific gravity3.17-3.19
Fusibility3.5
Solubilityinsoluble
Other CharacteristicsTenebrescence, chatoyancy, kunzite often fluorescent under UV

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 in size are reported from the Black Hills of South Dakota, United States.[1]

Crystals form in the monoclinic system and are typically heavily striated parallel to the principal axis. Crystal faces are often etched and pitted with triangular markings.

Spodumene 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 granites and pegmatites. Transparent material has long been used as a gemstone with varieties kunzite and hiddenite noted for their strong pleochroism. Source localities include Brazil, Madagascar, USA (North Carolina, California), Afghanistan, and Pakistan.

Additional recommended knowledge

Contents

Economic importance

Spodumene is an important source of lithium for use in ceramics, mobile phone and automotive batteries, medicine and as a fluxing agent. Lithium is extracted from spodumene by fusing in acid.

World production of lithium via spodumene is around 80,000 metric tonnes per annum, primarily from the Greenbushes pegmatite of Western Australia, and some Chinese and Chilean sources. Spodumene is becoming less important a source of lithium due to the emergence of alkaline brine lake sources in China and Argentina, which produce lithium carbonate and lithium hydroxide directly.

Kunzite

  Kunzite is a pink to lilac colored gemstone, a variety of spodumene with the color coming from minor to trace amounts of manganese. Some (but not all) kunzite used for gemstones has been heated to enhance its color. It was named in honor of New York mineralogist and gemologist George Frederick Kunz. It has been found in Brazil, USA, Canada, CIS, Mexico, Sweden, Western Australia, Afghanistan and Pakistan.

References

  • Anthony, John W., Bideaux, Richard A., Bladh, Kenneth W., and Nichols, Monte C. (1990): Handbook of Mineralogy: Mineral Data Publishing, Tucson, Arizona
  • Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., ISBN 0-471-80580-7
  • Kunz, George Frederick (1892) Gems and Precious Stones of North America. The Scientific Publishing Company, New York NY
  • Palache, C., Davidson, S. C., and Goranson, E.A. (1930) The Hiddenite deposit in Alexander County, N.Carolina. American Mineralogist Vol 15 No. 8 p. 280
  • Webster, R. (2000). Gems: Their sources, descriptions and identification (5th ed.), pp. 186-190. Great Britain: Butterworth-Heinemann.
  • Webmineral
  • Mindat.org
  1. ^ Robert Louis Bonewitz, 2005, Rock and Gem, London, Dorling Kindersley

See also

 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Spodumene". A list of authors is available in Wikipedia.
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