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Alexandrite
Alexandrite

Tortoiseshell
Tortoiseshell



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Alexandrite
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Tortoiseshell

Alexandrite and Tortoiseshell Optical Properties

1 Optical Properties
1.1 Luster
Vitreous
Not Available
1.2 Pleochroism
Not Available
Not Available
1.3 Dispersion
NANA
Fluorite Optical Properties
0.007 1
1.4 Transparency
Transparent, Transparent to nearly opaque
Gemmological Tables (2004)
1.5 Refractive Index
1.739-1.7701.540-1.560
Agate Opal
1 3.25
1.6 Optic Character
Biaxial/+
Not Available
1.7 Crystal System
Orthorhombic
Not Available
1.8 Birefringence
0.007-0.010Not Available
Achroite
0 0.296
1.9 Clarity
Transparent
OpaqueUlrich Henn and Claudio C. Milisenda

Alexandrite and Tortoiseshell Optic Character

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

Similar to their colors, Alexandrite and Tortoiseshell 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.