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Alexandrite
Alexandrite

Mellite
Mellite



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Alexandrite
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Mellite

Alexandrite and Mellite Optical Properties

Optical Properties

Luster

Vitreous
Vitreous

Pleochroism

-
Weak: yellowish brown yellowAnthony et al

Dispersion

0.020.01
0.005 1
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Transparency

Transparent, Transparent to nearly opaque
-

Refractive Index

1.739-1.7701.509-1.541
1 3.25
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Optic Character

Biaxial/+
-

Crystal System

Orthorhombic
-

Birefringence

0.007-0.0100.030
0 0.296
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Clarity

Transparent
TransparentUlrich Henn and Claudio C. Milisenda

Alexandrite and Mellite Optic Character

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

Alexandrite and Mellite Transparency

Similar to their colors, Alexandrite and Mellite 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, Alexandrite is Transparent and Transparent to nearly opaque while Alexandrite is Transparent and Transparent to nearly opaque in appearance.