Tourmaline and Allanite Optical Properties

Tourmaline

Allanite

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1 Optical Properties

1.1 Luster

Vitreous

Not Available

1.2 Pleochroism

typically moderate to 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

1.614-1.6661

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Trigonal

Not Available

1.8 Birefringence

0.014-0.0400.013-0.036

0 0.296

1.9 Clarity

Transparent

Not Available

Tourmaline and Allanite Optic Character

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

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