Thulite and Cordierite Iolite Optical Properties

Thulite

Cordierite Iolite

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1 Optical Properties

1.1 Luster

Vitreous

1.2 Pleochroism

Present

Strong trichroism: colorless to yellowish

1.3 Dispersion

NA0.02

0.007 1

1.4 Transparency

Opaque, Translucent, Opaque . May be translucent in thin backlit sections.

Transparent

1.5 Refractive Index

1.6951.542-1.578

1 3.25

1.6 Optic Character

Not Available

Biaxial/+

1.7 Crystal System

Orthorhombic

Not Available

1.8 Birefringence

0.006-0.0180.008-0.012

0 0.296

1.9 Clarity

OpaqueHerve Nicolas Lazzarelli

Transparent

Thulite and Cordierite Iolite Optic Character

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

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Thulite and Cordierite Iolite Transparency

Similar to their colors, Thulite 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, Thulite is Opaque, Opaque . May be translucent in thin backlit sections. and Translucent while Thulite is Opaque, Opaque . May be translucent in thin backlit sections. and Translucent in appearance.