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Sillimanite
Sillimanite

Nuummite
Nuummite



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Sillimanite
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Nuummite

Sillimanite and Nuummite Optical Properties

1 Optical Properties
1.1 Luster
Vitreous, Subadamantine, Silky
Not Available
1.2 Pleochroism
Colourless to pale brown to yellow
Not Available
1.3 Dispersion
NANA
Fluorite Optical Properties
0.007 1
1.4 Transparency
Transparent, Translucent
Gemmological Tables (2004) More from other references
1.5 Refractive Index
1.653-1.6851.635-1.663
Agate Opal
1 3.25
1.6 Optic Character
Not Available
Not Available
1.7 Crystal System
Orthorhombic
Not Available
1.8 Birefringence
0.020-0.0220.0170-0.230
Achroite
0 0.296
1.9 Clarity
Transparent
Gemmological Tables (2004) More from other references

Sillimanite and Nuummite Optic Character

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

Similar to their colors, Sillimanite and Nuummite 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.