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Andalusite
Andalusite

Alexandrite
Alexandrite



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Andalusite
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Alexandrite

Andalusite and Alexandrite Optical Properties

Optical Properties

Luster

Vitreous, Greasy
Vitreous

Pleochroism

strongly trichroic
-

Dispersion

0.020.02
0.005 1
👆🏻

Transparency

Transparent, Translucent
Transparent, Transparent to nearly opaque

Refractive Index

1.627-1.6501.739-1.770
1 3.25
👆🏻

Optic Character

-
Biaxial/+

Crystal System

Orthorhombic
Orthorhombic

Birefringence

0.009-0.0100.007-0.010
0 0.296
👆🏻

Clarity

Transparent
Transparent

Andalusite and Alexandrite Optic Character

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

Andalusite and Alexandrite Transparency

Similar to their colors, Andalusite 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, Andalusite is Transparent and Translucent while Andalusite is Transparent and Translucent in appearance.