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Onyx
Onyx

Mellite
Mellite



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Onyx
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Mellite

Onyx and Mellite Optical Properties

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1 Optical Properties
1.1 Luster
Vitreous
Vitreous
1.2 Pleochroism
Not Available
Weak: yellowish brown yellowAnthony et al
1.3 Dispersion
NANA
Fluorite Optical Properties
0.007 1
1.4 Transparency
Translucent, Opaque, Translucent to opaque
Gemmological Tables (2004) More from other references
1.5 Refractive Index
1.530-1.5431.509-1.541
Agate Opal
1 3.25
1.6 Optic Character
Not Available
Not Available
1.7 Crystal System
Trigonal
Not Available
1.8 Birefringence
Not Available0.030
Achroite
0 0.296
1.9 Clarity
OpaqueHerve Nicolas Lazzarelli
TransparentUlrich Henn and Claudio C. Milisenda

Onyx and Mellite Optic Character

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

Onyx and Mellite Transparency

Similar to their colors, Onyx and Mellite 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, Onyx is Opaque, Translucent and Translucent to opaque while Onyx is Opaque, Translucent and Translucent to opaque in appearance.