Difference between revisions of "Lepidolite" - New World Encyclopedia

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[[image:Lepidolita.jpeg|thumb|right|350px| <center> A sample of lepidolite from [[Brazil]].</center>]]
 
[[image:Lepidolita.jpeg|thumb|right|350px| <center> A sample of lepidolite from [[Brazil]].</center>]]
  
'''Lepidolite''' (KLi<sub>2</sub>Al(Al,Si)<sub>3</sub>O<sub>10</sub>(F,OH)<sub>2</sub>) is a lilac or rose-violet colored [[Silicate minerals|phyllosilicate]] [[mineral]] of the [[mica]] group that is a secondary source of [[lithium]].<ref>"Manual of Mineralogy, 20th Ed." by Cornelius Hurlbut and Cornelis Klein.</ref>  It is associated with other lithium-bearing minerals like [[spodumene]] in [[pegmatite]] bodies. It is one of the major sources of the rare [[alkali metal]]s, [[rubidium]] and [[caesium]].<ref>H. Nechamkin, ''The Chemistry of the Elements'', McGraw-Hill, New York, 1968.</ref>
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Once thought of as a single [[mineral]] species, '''lepidolite''' has been recently redefined as a series of minerals in the [[mica]] group.<ref>[http://www.mindat.org/min-2380.html Lepidolite.] ''Mindat.org''. Retrieved May 11, 2007.</ref> Chemically, it may be referred to as [[potassium]] [[lithium]] aluminosilicate. Its lithium content can vary, but the lithium-rich varieties form an important source of this element and are generally associated with other lithium-bearing minerals (such as [[spodumene]]) in [[pegmatite]] bodies. It is also one of the main sources of the rare [[alkali metal]]s, [[rubidium]] and [[cesium]].<ref>H. Nechamkin, ''The Chemistry of the Elements'' (New York: McGraw-Hill, 1968).</ref>
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== Characteristics ==
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The chemical formula of lepidolite may be written as KLi<sub>2</sub>Al(Al,Si)<sub>3</sub>O<sub>10</sub>(F,OH)<sub>2</sub>. It has a vitreous to pearly luster and ranges from transparent to translucent. Typically, its colors range from lilac to pale pink to white, but gray and yellow varieties have also been found occasionally.
  
===Physical Properties===
 
:Color: violet lombo pale pink to white, sometimes gray or yellow.
 
:Luster: vitreous to pearly
 
:Transparency: transparent to translucent.
 
 
:Crystal System: monoclinic; 2/m.
 
:Crystal System: monoclinic; 2/m.
 
:Crystal Habits: include tabular to prismatic crystals with a prominent pinacoid termination.  Lepidolite forms pseudo-hexagonal "books."  Also as micaceous or granular masses.
 
:Crystal Habits: include tabular to prismatic crystals with a prominent pinacoid termination.  Lepidolite forms pseudo-hexagonal "books."  Also as micaceous or granular masses.

Revision as of 00:05, 12 May 2007

A sample of lepidolite from Brazil.

Once thought of as a single mineral species, lepidolite has been recently redefined as a series of minerals in the mica group.[1] Chemically, it may be referred to as potassium lithium aluminosilicate. Its lithium content can vary, but the lithium-rich varieties form an important source of this element and are generally associated with other lithium-bearing minerals (such as spodumene) in pegmatite bodies. It is also one of the main sources of the rare alkali metals, rubidium and cesium.[2]

Characteristics

The chemical formula of lepidolite may be written as KLi2Al(Al,Si)3O10(F,OH)2. It has a vitreous to pearly luster and ranges from transparent to translucent. Typically, its colors range from lilac to pale pink to white, but gray and yellow varieties have also been found occasionally.

Crystal System: monoclinic; 2/m.
Crystal Habits: include tabular to prismatic crystals with a prominent pinacoid termination. Lepidolite forms pseudo-hexagonal "books." Also as micaceous or granular masses.
Cleavage: perfect in one direction perpendicular to the c-axis.
Fracture: uneven.
Hardness: 2.5
Specific Gravity: 2.8+
Streak: white
Density:2.8-2.9 Average size 2.84

Associated Minerals: quartz, feldspar, spodumene, amblygonite, tourmaline.

Notable Occurrences: Brazil; Ural Mountains, Russia; California; Tanco Pegmatite, Bernic Lake Manitoba, Canada.

See also

Notes

  1. Lepidolite. Mindat.org. Retrieved May 11, 2007.
  2. H. Nechamkin, The Chemistry of the Elements (New York: McGraw-Hill, 1968).

References
ISBN links support NWE through referral fees

  • Deer, W.A., R.A. Howie, and J. Zussman. 1996. An Introduction to the Rock-Forming Minerals. 2nd ed. Upper Saddle River, NJ: Prentice Hall. ISBN 0582300940.
  • Farndon, John. 2006. The Practical Encyclopedia of Rocks & Minerals: How to Find, Identify, Collect and Maintain the World's best Specimens, with over 1000 Photographs and Artworks. London: Lorenz Books. ISBN 0754815412.
  • Klein, Cornelis, and Barbara Dutrow. 2007. Manual of Mineral Science. 23rd ed. New York: John Wiley. ISBN 978-0471721574.
  • Pellant, Chris. 2002. Rocks and Minerals. Smithsonian Handbooks. New York: Dorling Kindersley. ISBN 0789491060.
  • Shaffer, Paul R., Herbert S. Zim, and Raymond Perlman. 2001. Rocks, Gems and Minerals. Rev. ed. New York: St. Martin's Press. ISBN 1582381321.

External links

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