Sapphire and Onyx Optical Properties

Sapphire

Onyx

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1 Optical Properties

1.1 Luster

Vitreous, Adamantine, Vitreous, Adamantine

Vitreous

1.2 Pleochroism

Strong

Not Available

1.3 Dispersion

0.02NA

0.007 1

1.4 Transparency

Transparent, Translucent, Transparent to opaque

Translucent, Opaque, Translucent to opaque

1.5 Refractive Index

1.762-1.7881.530-1.543

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Trigonal

1.8 Birefringence

0.008-0.009Not Available

0 0.296

1.9 Clarity

Transparent

OpaqueHerve Nicolas Lazzarelli

Sapphire and Onyx Optic Character

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

Similar to their colors, Sapphire and Onyx 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, Sapphire is Translucent, Transparent and Transparent to opaque while Sapphire is Translucent, Transparent and Transparent to opaque in appearance.