Tsilaisite
General
CategoryTourmaline
Formula
(repeating unit)		NaMn2+3Al6Si6O18(BO3)3(OH)3OH
IMA symbolTsl[1]
Crystal systemTrigonal
Identification
Mohs scale hardness7 to 7.5
LusterVitreous
StreakWhite

Tsilaisite is a manganese rich variety of elbaite tourmaline.[2] It is also known as Tsilaizite.[3] Tsilaisite is related Fluor-tsilaisite.[4] The gem is named after the location it was first found.[5]

History

It was first reported in the Tsilaisina (also called Tsilaizina) Mine in Vakinankaratra, Madagascar.[3]

The gem was originally described as tsilaisite. But then it was discredited in 2006. In 2011 it was reapproved as tsilaisite.[5]

Characteristics

Color

In plane polarized light, the gem is pleochroic.[6] Tsilaisite can be deep pink, red,[2] orangish-yellow, brownish-gold,[3] or greenish-yellow.[5]

Chemistry

Manganese makes up to 3% of the gem's chemistry.[3]

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. 1 2 Manutchehr-Danai, Mohsen (2013-03-09). Dictionary of Gems and Gemology. Springer Science & Business Media. p. 485. ISBN 978-3-662-04288-5.
  3. 1 2 3 4 "Tsilaisite". National Gem Lab. 2017-03-27. Retrieved 2021-09-27.
  4. ↑ Bosi, Ferdinando; Andreozzi, Giovanni B.; Agrosi, Giovanna; Scandale, Eugenio (February 2015). "Fluor-tsilaisite, NaMn3Al6(Si6O18)(BO3)3(OH)3F, a new tourmaline from San Piero in Campo (Elba, Italy) and new data on tsilaisitic tourmaline from the holotype specimen locality". Mineralogical Magazine. 79 (1): 89–101. doi:10.1180/minmag.2015.079.1.08. ISSN 0026-461X. S2CID 129149776.
  5. 1 2 3 "Tsilaisite". www.mindat.org. Retrieved 2021-09-27.
  6. ↑ Issues in Geology and Mineralogy: 2013 Edition. ScholarlyEditions. 2013-05-01. p. 677. ISBN 978-1-4901-0698-4.


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