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Alunite
Alunite

Mottramite
Mottramite



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Alunite
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Mottramite

Alunite and Mottramite Optical Properties

Optical Properties

Luster

Vitreous, Pearly
Greasy

Pleochroism

-
Visible X=Y= canary yellow to greenish yellow

Dispersion

0.020.04
0.005 1
👆🏻

Transparency

-
-

Refractive Index

1.5722.170
1 3.25
👆🏻

Optic Character

-
-

Crystal System

Trigonal
Orthorhombic

Birefringence

0.0200.150
0 0.296
👆🏻

Clarity

-
-

Alunite and Mottramite Optic Character

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

Similar to their colors, Alunite and Mottramite 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.