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Sillimanite
Sillimanite

Cassiterite
Cassiterite



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Sillimanite
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Cassiterite

Sillimanite and Cassiterite Optical Properties

Optical Properties

Luster

Vitreous, Subadamantine, Silky
Adamantine, Greasy

Pleochroism

Colourless to pale brown to yellow
Pleochroic haloes have been observed. Dichroic in yellow

Dispersion

0.020.07
0.005 1
👆🏻

Transparency

Transparent, Translucent
Transparent, Translucent

Refractive Index

1.653-1.6851.990-2.105
1 3.25
👆🏻

Optic Character

-
-

Crystal System

Orthorhombic
tetragonal

Birefringence

0.020-0.0220.096-0.098
0 0.296
👆🏻

Clarity

Transparent
Transparent

Sillimanite and Cassiterite Optic Character

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

Sillimanite and Cassiterite Transparency

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