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Dravite and Andalusite Optical Properties


Andalusite and Dravite Optical Properties


Optical Properties

Luster
Vitreous   
Vitreous, Greasy   

Pleochroism
Very strong: pale yellow colorless   
strongly trichroic   

Dispersion
0.02   
22
0.02   
23

Transparency
Transparent   
Transparent, Translucent   

Refractive Index
1.614-1.666   
1.627-1.650   

Optic Character
Not Available   
Not Available   

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

Birefringence
0.014-0.032   
0.009-0.010   

Clarity
Transparent   
Transparent   

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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.

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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.

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