Chemistry:Tsilaisite

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Tsilaisite
General
CategoryTourmaline
Formula
(repeating unit)
NaMn2+3Al6Si6O18(BO3)3(OH)3OH
Crystal systemTrigonal
Identification
Mohs scale hardness7 to 7.5
|re|er}}Vitreous
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