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Dravite
Dravite

Andalusite
Andalusite



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Dravite
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Andalusite

Dravite and Andalusite Optical Properties

Optical Properties

Luster

Vitreous
Vitreous, Greasy

Pleochroism

Very strong: pale yellow colorless
strongly trichroic

Dispersion

0.020.02
0.005 1
👆🏻

Transparency

Transparent
Transparent, Translucent

Refractive Index

1.614-1.6661.627-1.650
1 3.25
👆🏻

Optic Character

-
-

Crystal System

Trigonal Ditrigonal Pyramidal H-M Symbol (3m) Space Group: R 3m
Orthorhombic

Birefringence

0.014-0.0320.009-0.010
0 0.296
👆🏻

Clarity

Transparent
Transparent

Dravite and Andalusite Optic Character

Dravite and Andalusite optical properties play a significant role while distinguishing these gemstones from each other. These properties are influenced by the Dravite and Andalusite Physical Properties like crystallographic symmetry, pleochroism,etc. in the crystal. Some of the optical properties are refractive index, luster, optic character, pleochroism etc. Prominent among these is Dravite and Andalusite optic character. You might have noticed your gemologist rotating the gemstone while testing it. Rotating a gemstone along its optic axis helps in determining its optic character.

Dravite and Andalusite Transparency

Similar to their colors, Dravite and Andalusite transparency can also be used as criteria for their primary identification. Although transparency cannot be the only criteria for gemstone identification, it can efficiently used in gemstone grading. Talking about their transparency, Dravite is Transparent while Dravite is Transparent in appearance.