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Amethyst
Amethyst

Sillimanite
Sillimanite



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Amethyst
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Sillimanite

Amethyst and Sillimanite Optical Properties

Optical Properties

Luster

Vitreous
Vitreous, Subadamantine, Silky

Pleochroism

None
Colourless to pale brown to yellow

Dispersion

0.010.02
0.005 1
👆🏻

Transparency

Transparent, Transparent to translucent
Transparent, Translucent

Refractive Index

1.544-1.5531.653-1.685
1 3.25
👆🏻

Optic Character

-
-

Crystal System

Trigonal
Orthorhombic

Birefringence

0.0090.020-0.022
0 0.296
👆🏻

Clarity

Transparent
Transparent

Amethyst and Sillimanite Optic Character

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

Amethyst and Sillimanite Transparency

Similar to their colors, Amethyst 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, Amethyst is Transparent and Transparent to translucent while Amethyst is Transparent and Transparent to translucent in appearance.