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Spodumene

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Spodumene is a pyroxene member of inosilicate mineral with chemical formula is LiAl(SiO3)2, lithium aluminium. It can also be pink, lilac, or green. Crystals are prismatic, flattened, and typically striated along their length. Gem varieties of the mineral usually exhibit strong pleochroism. Spodumene is an important  ore of lithium. It occurs in lithium-bearing granite pegmatite dykes, often with other lithiumbearing minerals, such as eucryptite and lepidolite. One of the largest single crystals of any mineral ever found was a spodumene specimen from South Dakota, USA, 47 ft (14.3 m) long and 90 tons in weight.

Ordinary low temperature form α-spodumen is found in the monoclinic system, while high-temperature β-spodumen crystallizes in the tetragonal apparatus. Ordinary α-spodumen is converted to β-spodumen at temperatures above 900 ° C. The crystals are generally densely streaked parallel to the main axis. Crystal faces are usually scraped and pitted with triangular markings. (Wiki)

Name: From the Greek for ash-colored, in allusion to its color.

Association: Quartz, albite, petalite, eucryptite, lepidolite, beryl

Mineral Group: Pyroxene group

Chemical Properties

Chemical Classification Inosilicate
Formula LiAl(SiO3)2
Common Impurities Fe,Mn,Mg,Ca,Na,K,H2O

Spodumene Physical Properties

Crystal habit prismatic, generally flattened and elongated, striated parallel to {100}, commonly massive
Color Colourless, yellow, light green, emerald-green, pink to violet, purple, white, gray
Streak White
Luster Vitreous, Dull
Cleavage Perfect
Diaphaneity Transparent, Translucent
Mohs Hardness 6,5 – 7
Crystal System Monoclinic
Tenacity Brittle
Density 3.03–3.23
Fracture Uneven to subconchoidal
Other characteristics Tenebrescence, chatoyancy, kunzite often fluorescent under UV (Wikipedia)
Fusibility         3.5
Solubility         Insoluble

Spodumene Optical Properties

Color / Pleochroism Strong in kunzite: α-purple, γ-colorless; hiddenite: α-green, γ-colorless
2V: Measured: 54° to 69°, Calculated: 88°
RI values: nα = 1.648 – 1.661 nβ = 1.655 – 1.670 nγ = 1.662 – 1.679
Twinning Common on {100}
Optic Sign Biaxial (+)
Birefringence δ = 0.014 – 0.018
Relief Moderate
Dispersion: weak

Occurrence of Spodumene

Spodumen occurs in lithium-rich granite pegmatites, aplites and gneisses. Related minerals are: quartz, albite, petalite, eucryptite, lepidolite and beryl.

The obvious material has been used as a precious stone with its kunzite and hiddenite varieties which have attracted attention with their robust pleochroism for a long time. Resource locations include Afghanistan, Australia, Brazil, Madagascar, Pakistan, Quebec in Canada, and North Carolina, California in the USA.

Uses Area and Economic Importance

Spodumene is an essential supply of lithium to be used in ceramics, cell phones and car batteries, medicine, Pyroceram and as a fluent substance. it’s far extracted from spodumene with the aid of fusing in lithium acid.

World lithium production through spodumen is approximately 80,000 mt per year, mainly from the Greenbushes pegmatite of Western Australia and some Chinese and Chilean sources. The Talison mine at Greenbushes in Western Australia is reported to be the largest and the highest ore level at 2.4% Li2O (2012 figures).

Another important advantage that the spoiler has over the more popular saltwater competitors is the purity of the lithium carbonate it can produce. While all products used by the battery industry are at least 99.5% lithium carbonate, the formation of the remaining 0.5% is important; High amounts of iron, magnesium or other harmful materials make the brine less attractive product.

Gemstone Varieties

Hiddenite: The emerald green spodümen type is colored with chromium like emerald. Not all green spodumens are tinted with chrome, which tends to have a lighter color and is therefore not hidden.

Kunzite: Kunzite is a colorful gemstone that changes from pink to lilac, with a small amount of trace color and various spodumens of manganese colors. Some (not all) used for gemstones are heated to increase the color of kunzite. Also, it is irradiated frequently to improve color.

Triphane: Triphane is a yellow Spodumene variety.

Distribution

  • From Uto, Sodermanland, and in the Varutrask pegmatite, 15 km northwest of Skelleftea, Vasterbotten, Sweden.
  • In Finland, from near Kuortane, and in the Tammela district.
  • In the USA, giant crystals in the Etta mine, near Keystone, Pennington Co., and elsewhere in the Black Hills, South Dakota; at Hiddenite, Alexander Co. and in the Foote mine, Kings Mountain, Cleveland Co., North Carolina; from the Pala district, San Diego Co., California; and in the Harding mine, Dixon, Taos Co., New Mexico.
  • From the Tanco mine, Bernic Lake, Manitoba, Canada.
  • At the Urupuca mine, Itambacari, and at Resplendor, Minas Gerais, Brazil.
  • From Mawi and Kantiva, Nuristan district, Laghman Province, Afghanistan.
  • At Maharitra, Mt. Bity, and at Anjanabonoina, Madagascar.
  • From Bikita, Zimbabwe. Many other minor localities are known.

References

  • Bonewitz, R. (2012). Rocks and minerals. 2nd ed. London: DK Publishing.
  • Dana, J. D. (1864). Manual of Mineralogy… Wiley.
  • Handbook of Mineralogy. [online] Available at: http://www.handbookofmineralogy.org [Accessed 4 Mar. 2019].
  • Mineral information, data and localities.. [online] Available at: https://www.mindat.org/ [Accessed. 2019].
  • Wikipedia contributors. (2019, March 21). Spodumene. In Wikipedia, The Free Encyclopedia. Retrieved 23:32, July 7, 2019, from https://en.wikipedia.org/w/index.php?title=Spodumene&oldid=888757472
Cite this article as: Geology Science. (2019). Spodumene. [online] Available at: http://geologyscience.com/minerals/spodumene/ [20th October 2019 ]
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