Colemanite

Colemanite
General
CategoryInoborates
FormulaCa2B6O11·5H2O
IMA symbolCole
Strunz classification6.CB.10
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP21/a
Unit cella = 8.712(2) Å,
b = 11.247(3) Å,
c = 6.091(1) Å;
β = 110.12°; Z = 4
Identification
ColorColorless, white, yellowish, grey
Crystal habitMassive granular to coarsely crystalline, most commonly nodular.
Cleavage[010] perfect, [001] distinct
FractureBrittle uneven to subconchoidal
Mohs scale hardness4.5
LusterVitreous
StreakWhite
DiaphaneityTransparent to translucent
Specific gravity2.42
Optical propertiesBiaxial (+)
Refractive indexnα = 1.586 nβ = 1.592 nγ = 1.614
Birefringenceδ = 0.028
Fusibility1.5
Diagnostic featuresExfoliates on heating, produces a green flame
Other characteristicsBright pale yellow fluorescence, may phosphoresce pale green; pyroelectric and piezoelectric at very low temperature.
References

Colemanite (Ca2B6O11·5H2O) or (CaB3O4(OH)3·H2O) is a borate mineral found in evaporite deposits of alkaline lacustrine environments. Colemanite is a secondary mineral that forms by alteration of borax and ulexite.

It was first described in 1884 for an occurrence near Furnace Creek in Death Valley and was named after William Tell Coleman (1824–1893), owner of the mine "Harmony Borax Works" where it was first found. At the time, Coleman had alternatively proposed the name "smithite" instead after his business associate Francis Marion Smith.

Uses

Colemanite was the most important ore of boron until the discovery of kernite in 1926. It has many industrial uses such as in heat resistant glass manufacturing.

Occurrence

About 40% of the world's known colemanite reserves are at the Emet mine in western Turkey. Other important sources in Turkey are found at Bigadiç and Kestelek.

See also

References

  1. ↑ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ↑ Schorn, Stefan; et al. (2021). "Colemanit (Colemanite)". Mineralienatlas.
  3. 1 2 Klein, Cornelis; Hurlbut, Cornelius S. Jr. (1993). Manual of mineralogy: (after James D. Dana) (21st ed.). New York: Wiley. p. 422. ISBN 0-471-57452-X.
  4. 1 2 3 "Colemanite". mindat.org. Retrieved 30 December 2021.
  5. ↑ "Colemanite mineral data". Webmineral. Retrieved 30 December 2021.
  6. 1 2 Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (2005). "Colemanite" (PDF). Handbook of Mineralogy.
  7. ↑ Hildebrand, GH. (1982) Borax Pioneer: Francis Marion Smith. San Diego: Howell-North Books. p 31 ISBN 0-8310-7148-6
  8. ↑ "Nitrates". Simon & Schuster's Guide to Rocks and Minerals. Simon & Schuster. 1977. p. entry 111. ISBN 978-0-671-24417-0.
  9. ↑ "Emet". Eti Maden. Retrieved 29 November 2024.
  10. ↑ "Country Profile – Boron Turkey". Borates Today. 25 September 2021. Retrieved 29 November 2024.