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Dravite
Dravite

Alunite
Alunite



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Dravite
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Alunite

Dravite and Alunite Optical Properties

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Optical Properties

Luster

Vitreous
Vitreous, Pearly

Pleochroism

Very strong: pale yellow colorless
-

Dispersion

0.020.02
0.005 1
👆🏻

Transparency

Transparent
-

Refractive Index

1.614-1.6661.572
1 3.25
👆🏻

Optic Character

-
-

Crystal System

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

Birefringence

0.014-0.0320.020
0 0.296
👆🏻

Clarity

Transparent
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Dravite and Alunite Optic Character

Dravite and Alunite optical properties play a significant role while distinguishing these gemstones from each other. These properties are influenced by the Dravite and Alunite 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 Alunite 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 Alunite Transparency

Similar to their colors, Dravite and Alunite 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.