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Alunite
Alunite

Opal
Opal



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Alunite
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Opal

Alunite and Opal Optical Properties

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Optical Properties

Luster

Vitreous, Pearly
Vitreous, Pearly

Pleochroism

-
None

Dispersion

0.020.01
0.005 1
👆🏻

Transparency

-
Transparent, Translucent, Transparent to translucent

Refractive Index

1.5721.37-1.52
1 3.25
👆🏻

Optic Character

-
-

Crystal System

Trigonal
Trigonal

Birefringence

0.020-9999
0 0.296
👆🏻

Clarity

-
Transparent

Alunite and Opal Optic Character

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

Alunite and Opal Transparency

Similar to their colors, Alunite and Opal 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, Alunite is while Alunite is in appearance.