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Allanite
Allanite

Dravite
Dravite



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Allanite
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Dravite

Allanite and Dravite Optical Properties

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Optical Properties

Luster

-
Vitreous

Pleochroism

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Very strong: pale yellow colorless

Dispersion

0.020.02
0.005 1
👆🏻

Transparency

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Transparent

Refractive Index

11.614-1.666
1 3.25
👆🏻

Optic Character

-
-

Crystal System

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

Birefringence

0.013-0.0360.014-0.032
0 0.296
👆🏻

Clarity

-
Transparent

Allanite and Dravite Optic Character

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

Allanite and Dravite Transparency

Similar to their colors, Allanite and Dravite 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, Allanite is while Allanite is in appearance.