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Corundum
Corundum

Alexandrite
Alexandrite



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Corundum
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Alexandrite

Corundum and Alexandrite Optical Properties

1 Optical Properties
1.1 Luster
Adamantine, Vitreous
Vitreous
1.2 Pleochroism
None
Not Available
1.3 Dispersion
0.02NA
Fluorite Optical Properties
0.007 1
1.4 Transparency
Transparent, Translucent
Transparent, Transparent to nearly opaque
1.5 Refractive Index
1.758-1.7801.739-1.770
Agate Opal
1 3.25
1.6 Optic Character
Not Available
Biaxial/+
1.7 Crystal System
Trigonal
Orthorhombic
1.8 Birefringence
0.007-0.0100.007-0.010
Achroite
0 0.296
1.9 Clarity
Gemmological Tables (2004) More from other references
Transparent

Corundum and Alexandrite Optic Character

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

Corundum and Alexandrite Transparency

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