Sapphire and Sillimanite Optical Properties

Sapphire

Sillimanite

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1 Optical Properties

1.1 Luster

Vitreous, Adamantine, Vitreous, Adamantine

Vitreous, Subadamantine, Silky

1.2 Pleochroism

Strong

Colourless to pale brown to yellow

1.3 Dispersion

Albite Optical ..

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0.02

Rank: 21 (Overall)▶

Not Available

Rank: N/A (Overall)▶

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Fluorite Optical Properties

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0.044 (Anglesite Opt..)

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1.4 Transparency

Transparent, Translucent, Transparent to opaque

Transparent, Translucent

1.5 Refractive Index

1.762-1.788

1.653-1.685

1.6 Optic Character

Not Available

1.7 Crystal System

Trigonal

Orthorhombic

1.8 Birefringence

0.008-0.009

0.020-0.022

1.9 Clarity

Transparent

Sapphire and Sillimanite Optic Character

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

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Sapphire and Sillimanite Transparency

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