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Onyx
Onyx

Cordierite Iolite
Cordierite Iolite



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Onyx
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Cordierite Iolite

Onyx and Cordierite Iolite Optical Properties

1 Optical Properties
1.1 Luster
Vitreous
Vitreous
1.2 Pleochroism
Not Available
Strong trichroism: colorless to yellowish
1.3 Dispersion
NA0.02
Fluorite Optical Properties
0.007 1
1.4 Transparency
Translucent, Opaque, Translucent to opaque
Transparent
1.5 Refractive Index
1.530-1.5431.542-1.578
Agate Opal
1 3.25
1.6 Optic Character
Not Available
Biaxial/+
1.7 Crystal System
Trigonal
Not Available
1.8 Birefringence
Not Available0.008-0.012
Achroite
0 0.296
1.9 Clarity
OpaqueHerve Nicolas Lazzarelli
Transparent

Onyx and Cordierite Iolite Optic Character

Onyx and Cordierite Iolite optical properties play a significant role while distinguishing these gemstones from each other. These properties are influenced by the Onyx and Cordierite Iolite 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 Cordierite Iolite 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. Cordierite Iolite has Biaxial/+ character.

Onyx and Cordierite Iolite Transparency

Similar to their colors, Onyx and Cordierite Iolite 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.