Opal and Dravite Optical Properties

Opal

Dravite

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1 Optical Properties

1.1 Luster

Vitreous, Pearly

Vitreous

1.2 Pleochroism

None

Very strong: pale yellow colorless

1.3 Dispersion

None0.02

0.007 1

1.4 Transparency

Transparent, Translucent, Transparent to translucent

Transparent

1.5 Refractive Index

1.37-1.521.614-1.666

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Trigonal

Trigonal Ditrigonal Pyramidal H-M Symbol (3m) Space Group: R 3m

1.8 Birefringence

Not Available0.014-0.032

0 0.296

1.9 Clarity

Transparent

Opal and Dravite Optic Character

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

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