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Corundum
Corundum

Sillimanite
Sillimanite



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Corundum
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Sillimanite

Corundum and Sillimanite Optical Properties

1 Optical Properties
1.1 Luster
Adamantine, Vitreous
Vitreous, Subadamantine, Silky
1.2 Pleochroism
None
Colourless to pale brown to yellow
1.3 Dispersion
0.02NA
Fluorite Optical Properties
0.007 1
1.4 Transparency
Transparent, Translucent
Transparent, Translucent
1.5 Refractive Index
1.758-1.7801.653-1.685
Agate Opal
1 3.25
1.6 Optic Character
Not Available
Not Available
1.7 Crystal System
Trigonal
Orthorhombic
1.8 Birefringence
0.007-0.0100.020-0.022
Achroite
0 0.296
1.9 Clarity
Gemmological Tables (2004) More from other references
Transparent

Corundum and Sillimanite Optic Character

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

Corundum and Sillimanite Transparency

Similar to their colors, Corundum and Sillimanite 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.