Sapphire and Allanite Optical Properties

Sapphire

Allanite

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1 Optical Properties

1.1 Luster

Vitreous, Adamantine, Vitreous, Adamantine

Not Available

1.2 Pleochroism

Strong

Not Available

1.3 Dispersion

0.02NA

0.007 1

1.4 Transparency

Transparent, Translucent, Transparent to opaque

Not Available

1.5 Refractive Index

1.762-1.7881

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Trigonal

Not Available

1.8 Birefringence

0.008-0.0090.013-0.036

0 0.296

1.9 Clarity

Transparent

Not Available

Sapphire and Allanite Optic Character

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

Similar to their colors, Sapphire and Allanite 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.