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Dumortierite
Dumortierite

Dravite
Dravite



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X
Dumortierite
X
Dravite

Dumortierite and Dravite Optical Properties

Optical Properties

Luster

Vitreous
Vitreous

Pleochroism

Strong; X = deep blue or violet; Y = yellow to red-violet or nearly colorless; Z = colorless or very pale blue
Very strong: pale yellow colorless

Dispersion

0.010.02
0.005 1
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Transparency

Translucent, Translucent to opaque
Transparent

Refractive Index

1.669-1.7231.614-1.666
1 3.25
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Optic Character

-
-

Crystal System

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

Birefringence

0.011-0.0370.014-0.032
0 0.296
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Clarity

Translucent
Transparent

Dumortierite and Dravite Optic Character

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

Dumortierite and Dravite Transparency

Similar to their colors, Dumortierite 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, Dumortierite is Translucent and Translucent to opaque while Dumortierite is Translucent and Translucent to opaque in appearance.