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Sillimanite
Sillimanite

Thulite
Thulite



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Sillimanite
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Thulite

Sillimanite and Thulite Optical Properties

1 Optical Properties
1.1 Luster
Vitreous, Subadamantine, Silky
Vitreous
1.2 Pleochroism
Colourless to pale brown to yellow
Present
1.3 Dispersion
NANA
Fluorite Optical Properties
0.007 1
1.4 Transparency
Transparent, Translucent
Opaque, Translucent, Opaque . May be translucent in thin backlit sections.
1.5 Refractive Index
1.653-1.6851.695
Agate Opal
1 3.25
1.6 Optic Character
Not Available
Not Available
1.7 Crystal System
Orthorhombic
Orthorhombic
1.8 Birefringence
0.020-0.0220.006-0.018
Achroite
0 0.296
1.9 Clarity
Transparent
OpaqueHerve Nicolas Lazzarelli

Sillimanite and Thulite Optic Character

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

Sillimanite and Thulite Transparency

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