Opal and Sellaite Optical Properties

Opal

Sellaite

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1 Optical Properties

1.1 Luster

Vitreous, Pearly

Vitreous

1.2 Pleochroism

None

Not Available

1.3 Dispersion

NoneNA

0.007 1

1.4 Transparency

Transparent, Translucent, Transparent to translucent

Transparent

1.5 Refractive Index

1.37-1.521.378-1.390

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Trigonal

tetragonal

1.8 Birefringence

Not Available0.012

0 0.296

1.9 Clarity

Transparent

Opal and Sellaite Optic Character

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

Similar to their colors, Opal and Sellaite 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.