Thulite and Alexandrite Optical Properties

Thulite

Alexandrite

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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, Transparent to nearly opaque

1.5 Refractive Index

1.6951.739-1.770

1 3.25

1.6 Optic Character

Not Available

Biaxial/+

1.7 Crystal System

Orthorhombic

1.8 Birefringence

0.006-0.0180.007-0.010

0 0.296

1.9 Clarity

OpaqueHerve Nicolas Lazzarelli

Transparent

Thulite and Alexandrite Optic Character

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

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Thulite and Alexandrite Transparency

Similar to their colors, Thulite and Alexandrite 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.