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Mellite
Mellite

Sillimanite
Sillimanite



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Mellite
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Sillimanite

Mellite and Sillimanite Optical Properties

Optical Properties

Luster

Vitreous
Vitreous, Subadamantine, Silky

Pleochroism

Weak: yellowish brown yellowAnthony et al
Colourless to pale brown to yellow

Dispersion

0.010.02
0.005 1
👆🏻

Transparency

-
Transparent, Translucent

Refractive Index

1.509-1.5411.653-1.685
1 3.25
👆🏻

Optic Character

-
-

Crystal System

-
Orthorhombic

Birefringence

0.0300.020-0.022
0 0.296
👆🏻

Clarity

TransparentUlrich Henn and Claudio C. Milisenda
Transparent

Mellite and Sillimanite Optic Character

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

Mellite and Sillimanite Transparency

Similar to their colors, Mellite 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, Mellite is while Mellite is in appearance.