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Amethyst
Amethyst

Alexandrite
Alexandrite



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Amethyst
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Alexandrite

Amethyst and Alexandrite Optical Properties

Optical Properties

Luster

Vitreous
Vitreous

Pleochroism

None
-

Dispersion

0.010.02
0.005 1
👆🏻

Transparency

Transparent, Transparent to translucent
Transparent, Transparent to nearly opaque

Refractive Index

1.544-1.5531.739-1.770
1 3.25
👆🏻

Optic Character

-
Biaxial/+

Crystal System

Trigonal
Orthorhombic

Birefringence

0.0090.007-0.010
0 0.296
👆🏻

Clarity

Transparent
Transparent

Amethyst and Alexandrite Optic Character

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

Amethyst and Alexandrite Transparency

Similar to their colors, Amethyst 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, Amethyst is Transparent and Transparent to translucent while Amethyst is Transparent and Transparent to translucent in appearance.