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Spodumene

Walnut Hill Pegmatite Prospect, Huntington,Hampshire County, Massachusetts, USA (Size: 14.2

x 9.2 x 3.0 cm)General

Category Silicate mineral, pyroxeneFormula(repeating unit)

lithium aluminium silicate,LiAl(SiO3)2

Crystalsymmetry

Monoclinic 2/m

Unit cell a = 9.46 , b = 8.39 , c = 5.22 ; = 110.17; Z = 4

IdentificationColor Highly variable: white, colorless,

gray, pink, lilac, violet, yellow andgreen, may be bicolored; emeraldgreen - hiddenite; lilac - kunzite

SpodumeneFrom Wikipedia, the free encyclopedia

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

Spodumene is a pyroxene mineral consisting of lithiumaluminium inosilicate, LiAl(SiO3)2, and is a source oflithium. It occurs as colorless to yellowish, purplish, orlilac kunzite (see below), yellowish-green or emerald-green hiddenite, prismatic crystals, often of great size.Single crystals of 14.3 m (47 ft) in size are reported fromthe Black Hills of South Dakota, United States.[5]

The normal low-temperature form -spodumene is in themonoclinic system whereas the high-temperature -spodumene crystallizes in the tetragonal system. Thenormal -spodumene converts to -spodumene attemperatures above 900 C.[4] Crystals are typicallyheavily striated parallel to the principal axis. Crystal facesare often etched and pitted with triangular markings.

Contents1 Discovery and occurrence2 Economic importance3 Gemstone varieties

3.1 Hiddenite3.2 Kunzite

4 See also5 Notes6 References7 External links

Discovery and occurrenceSpodumene was first described in 1800 for an occurrencein the type locality in Ut, Sdermanland, Sweden. It wasdiscovered by Brazilian naturalist Jose Bonifacio deAndrada e Silva. The name is derived from the Greekspodumenos (), meaning "burnt to ashes,"owing to the opaque, ash-grey appearance of materialrefined for use in industry.[1]



Crystal habit prismatic, generally flattened andelongated, striated parallel to{100}, commonly massive

Crystalsystem

Monoclinic; 2/m

Twinning Common on {100}Cleavage Perfect prismatic, two directions

{110} {110} at 87Fracture Uneven to subconchoidalTenacity BrittleMohs scalehardness

6.57

Luster Vitreous, pearly on cleavageStreak whiteSpecificgravity

3.033.23

Opticalproperties

Biaxial (+)

Refractiveindex

n = 1.6481.661 n = 1.6551.670n = 1.6621.679

Birefringence = 0.0140.018Pleochroism Strong in kunzite: -purple, -

colorless; hiddenite: -green, -colorless

2V angle 54 to 69Fusibility 3.5Solubility insolubleOthercharacteristics

Tenebrescence, chatoyancy, kunziteoften fluorescent under UV

References [1][2][3][4]

Spodumene occurs in lithium-rich granite pegmatites andaplites. Associated minerals include: quartz, albite,petalite, eucryptite, lepidolite and beryl.[2]

Transparent material has long been used as a gemstonewith varieties kunzite and hiddenite noted for their strongpleochroism. Source localities include Afghanistan,Australia, Brazil, Madagascar, Pakistan, Qubec inCanada and North Carolina, California in the USA.

Economic importanceSpodumene is an important source of lithium for use inceramics, mobile phone and automotive batteries,medicine, Pyroceram and as a fluxing agent. Lithium isextracted from spodumene by fusing in acid.

World production of lithium via spodumene is around80,000 metric tonnes per annum, primarily from theGreenbushes pegmatite of Western Australia and fromsome Chinese and Chilean sources. The Talison mine inGreenbushes, Western Australia has an estimated reserveof 13 million tonnes.[6]

Some think that spodumene will become a less importantsource of lithium due to the emergence of alkaline brinelake sources in Chile, China and Argentina, whichproduce lithium chloride directly. Lithium chloride isconverted to lithium carbonate and lithium hydroxide byreaction with sodium carbonate and calcium hydroxiderespectively. However, pegmatite-based projects benefitfrom being quicker to move into production than brines,which can take 18 months to 3 years, depending onevaporation rates. With pegmatites, once a mill is built,the production of lithium carbonate takes only a matter ofdays.

Another key advantage that spodumene has over its morepopular brine rivals is the purity of the lithium carbonate itcan produce. While all product used by the battery industry has to grade at least 99.5% lithium carbonate, themakeup of the remaining 0.5% is important; higher amounts of iron, magnesium or other deleteriousmaterials make for a less attractive product.

Gemstone varietiesHiddenite



Hiddenite is a pale emerald green gem variety first reported from Alexander County, North Carolina, U. S.A.

This emerald green variety of spodumene is colored by chromium, just like emeralds. Not all greenspodumene is colored with chromium, which tend to have a lighter color, and therefore are not truehiddenite.

KunziteKunzite is a pink to lilac colored gemstone, a variety of spodumene with the color coming from minor totrace amounts of manganese. Some (but not all) kunzite used for gemstones has been heated to enhance itscolor. It is also frequently irradiated to enhance the color. Many kunzites fade when exposed to sunlight.

Kunzite was discovered in 1902, and was named after George Frederick Kunz, Tiffany & Co's chief jewelerat the time, and a noted mineralogist. It has been found in Brazil, USA, Canada, CIS, Mexico, Sweden,Western Australia, Afghanistan and Pakistan.

One notable example of kunzite used in jewellery is in the Russian Palmette tiara and necklace worn by theDuchess of Gloucester.[7]

An almost colorless kunzite crystal(upper left), a cut pale pink kunzite(upper right) and a greenish hiddenitecrystal (below) (unknown scale)

Kunzite Nouristan

See alsoList of mineralsGeorge Frederick Kunz

Notes1. Spodumene (http://www.mindat.org/min-3733.html), Mindat.org



Wikimedia Commons hasmedia related toSpodumene.

2. Anthony, John W., Bideaux, Richard A., Bladh, Kenneth W., and Nichols, Monte C. (1990). Handbook ofMineralogy (http://rruff.geo.arizona.edu/doclib/hom/spodumene.pdf). Mineral Data Publishing, Tucson, Arizona

3. Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., ISBN 0-471-80580-74. Deer, Howie and Zussman, Rock Forming Minerals, v. 2 Chain Silicates, Wiley, 1963 pp. 92-985. Robert Louis Bonewitz, 2005, Rock and Gem, London, Dorling Kindersley6. "Spodumene" (http://www.byport.com.au/index.htm?page=/bpa.html). Bunbury Port Authority. February 26, 2008.

Retrieved 2008-11-27.7. State Visit from India: HRH The Duchess of Gloucester (http://madhattery.royalroundup.com/2009/10/state-visit-

from-india-hrh-the-duchess-of-gloucester/), madhattery.com

ReferencesKunz, George Frederick (1892). Gems and Precious Stones of North America. New York: TheScientific Publishing Company.Palache, C., Davidson, S. C., and Goranson, E. A. (1930). "The Hiddenite deposit in AlexanderCounty, N. Carolina". American Mineralogist Vol. 15 No. 8 p. 280Webster, R. (2000). Gems: Their Sources, Descriptions and Identification (5th ed.), pp. 186190.Great Britain: Butterworth-Heinemann.The key players in Quebec lithium (http://www.northernminer.com/issues/story.aspx?aid=1000381706&link_source=aypr_NM&issue=08112010&link_targ=DailyNews), Daily News,The Northern Miner. August 11, 2010.

External links Texts on Wikisource:

"Kunzite". Encyclopdia Britannica (11th ed.). 1911.Frederick William Rudler (1911). "Spodumene".Encyclopdia Britannica (11th ed.)."Spodumene". New International Encyclopedia. 1905.

Retrieved from "https://en.wikipedia.org/w/index.php?title=Spodumene&oldid=660477355"

Categories: Aluminium minerals Gemstones Inosilicates Lithium minerals Monoclinic mineralsPyroxene group

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