Tourmaline and Cordierite Iolite Optical Properties

Tourmaline

Cordierite Iolite

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1 Optical Properties

1.1 Luster

Vitreous

1.2 Pleochroism

typically moderate to strong

Strong trichroism: colorless to yellowish

1.3 Dispersion

0.020.02

0.007 1

1.4 Transparency

Transparent, Translucent, Transparent to opaque

Transparent

1.5 Refractive Index

1.614-1.6661.542-1.578

1 3.25

1.6 Optic Character

Not Available

Biaxial/+

1.7 Crystal System

Trigonal

Not Available

1.8 Birefringence

0.014-0.0400.008-0.012

0 0.296

1.9 Clarity

Transparent

Tourmaline and Cordierite Iolite Optic Character

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

Compare Semi Precious Gemstones

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Tourmaline and Cordierite Iolite Transparency

Similar to their colors, Tourmaline and Cordierite Iolite 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.