Tourmaline and Franklinite Optical Properties

Tourmaline

Franklinite

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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

Translucent

1.5 Refractive Index

1.614-1.666Not Available

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Trigonal

Isometric Hexoctahedral H-M Symbol (4/m 3 2/m) Space Group: F d3m

1.8 Birefringence

0.014-0.040Not Available

0 0.296

1.9 Clarity

Transparent

Translucent

Tourmaline and Franklinite Optic Character

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

Similar to their colors, Tourmaline and Franklinite 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.