Chrysoberyl and Sillimanite Optical Properties

Chrysoberyl

Sillimanite

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Optical Properties

Luster

Vitreous

Vitreous, Subadamantine, Silky

Pleochroism

X = red; Y = yellow-orange; Z = emerald-green

Colourless to pale brown to yellow

Dispersion

0.020.02

0.005 1

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Transparency

Transparent, Translucent, Transparent to translucent

Transparent, Translucent

Refractive Index

1.746-1.7631.653-1.685

1 3.25

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Optic Character

Biaxial/+

Crystal System

Orthorhombic

Birefringence

0.007-0.0130.020-0.022

0 0.296

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Clarity

Transparent

Chrysoberyl and Sillimanite Optic Character

Chrysoberyl and Sillimanite optical properties play a significant role while distinguishing these gemstones from each other. These properties are influenced by the Chrysoberyl 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 Chrysoberyl 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. Chrysoberyl has Biaxial/+ character.

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Chrysoberyl and Sillimanite Transparency

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