To learn more about the mineralogy of the achroite, see mindat.org
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Achroite
- Translations : Achroite
- Synonym : white tourmaline
- Etymology : From the greek "a" = without and "chromos" = color, either without color.
- Comment : A variety of Tourmaline, colorless. Possible confusion with Damburite, Apatite, etc...
Gemological data
- Chemical formula : Na(LiAl)3Al6(BO3)3[Si6O18](OH)4
- Hardness (Mohs) : 7 à 8
- Density : 2.84 à 3.20 usually 3.05
- Refractive index : Ne=1,603 to 1,634 No=1,619 to 1,655
- Birefingence : biaxe negativ, -0,013 à 0,024
- Crystal system : Trigonal
- Group : Tourmaline
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