Opal and Sapphire Optical Properties

Opal

Sapphire

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Optical Properties

Luster

Pleochroism

Dispersion

Transparency

Refractive Index

Optic Character

Crystal System

Birefringence

Clarity

Vitreous, Pearly

None

0.01

Transparent, Translucent, Transparent to translucent

1.37-1.52

Trigonal

-9999

Transparent

Vitreous, Adamantine

Strong

0.02

Transparent, Translucent, Transparent to opaque

1.762-1.788

Trigonal

0.008-0.009

Transparent

Opal and Sapphire Optic Character

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

Similar to their colors, Opal and Sapphire 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, Opal is Transparent, Translucent and Transparent to translucent while Opal is Transparent, Translucent and Transparent to translucent in appearance.