Onyx and Purpurite Optical Properties

Onyx

Purpurite

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1 Optical Properties

1.1 Luster

Vitreous

Not Available

1.2 Pleochroism

Not Available

StrongArthur Thomas

1.3 Dispersion

NANA

0.007 1

1.4 Transparency

Translucent, Opaque, Translucent to opaque

TranslucentWalter Schumann, Gemstones of the world (2001) More from other references

1.5 Refractive Index

1.530-1.5431.85-1.92

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Trigonal

Orthorhombic

1.8 Birefringence

Not Available0.070

0 0.296

1.9 Clarity

OpaqueHerve Nicolas Lazzarelli

TranslucentWalter Schumann

Onyx and Purpurite Optic Character

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

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Onyx and Purpurite Transparency

Similar to their colors, Onyx and Purpurite 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.