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16.14.02: Achroite

Last updated

May 6, 2022
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- 16.14.01: Liddicoatite
- 16.14.03: Bi-color

gemology
Gemology Project

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Achroite Tourmaline
Chemical composition	Complex borosilicate
Crystal system	Trigonal
Habit	Prismatic
Cleavage	None
Fracture	Conchoidal
Hardness	7- 7.5
Optic nature	Uniaxial -
Refractive index	1.62 - 1.64
Birefringence	0.014 - 0.040
Dispersion	Low, 0.017
Specific gravity	3.01 - 3.11
Lustre	Vitreous
Pleochroism	Strong