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Nepheline
Nepheline

Sillimanite
Sillimanite



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Nepheline
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Sillimanite

Nepheline and Sillimanite Optical Properties

1 Optical Properties
1.1 Luster
Vitreous, Greasy
Vitreous, Subadamantine, Silky
1.2 Pleochroism
Not Available
Colourless to pale brown to yellow
1.3 Dispersion
NANA
Fluorite Optical Properties
0.007 1
1.4 Transparency
Transparent, Translucent
Transparent, Translucent
1.5 Refractive Index
1.529-1.5471.653-1.685
Agate Opal
1 3.25
1.6 Optic Character
Not Available
Not Available
1.7 Crystal System
Hexagonal
Orthorhombic
1.8 Birefringence
0.003-0.0040.020-0.022
Achroite
0 0.296
1.9 Clarity
Transparent
Transparent

Nepheline and Sillimanite Optic Character

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

Nepheline and Sillimanite Transparency

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