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Diamond
Diamond

Sillimanite
Sillimanite



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Diamond
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Sillimanite

Diamond and Sillimanite Optical Properties

Optical Properties

Luster

Adamantine
Vitreous, Subadamantine, Silky

Pleochroism

None
Colourless to pale brown to yellow

Dispersion

0.040.02
0.005 1
👆🏻

Transparency

Transparent, Translucent, Transparent to opaque
Transparent, Translucent

Refractive Index

2.417-2.4191.653-1.685
1 3.25
👆🏻

Optic Character

-
-

Crystal System

cubic
Orthorhombic

Birefringence

-99990.020-0.022
0 0.296
👆🏻

Clarity

Transparent
Transparent

Diamond and Sillimanite Optic Character

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

Diamond and Sillimanite Transparency

Similar to their colors, Diamond and Sillimanite 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, Diamond is Transparent, Translucent and Transparent to opaque while Diamond is Transparent, Translucent and Transparent to opaque in appearance.