Thulite and Iolite Optical Properties

Thulite

Iolite

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1 Optical Properties

1.1 Luster

Vitreous

1.2 Pleochroism

Present

Not Available

1.3 Dispersion

NANA

0.007 1

1.4 Transparency

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

Transparent, Translucent, Transparent to translucent

1.5 Refractive Index

1.6951.52-1.56

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Orthorhombic

1.8 Birefringence

0.006-0.018Not Available

0 0.296

1.9 Clarity

OpaqueHerve Nicolas Lazzarelli

Transparent to translucent

Thulite and Iolite Optic Character

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

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Thulite and Iolite Transparency

Similar to their colors, Thulite and 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.