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Polyhalite
Polyhalite

Mellite
Mellite



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Polyhalite
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Mellite

Polyhalite and Mellite Optical Properties

Optical Properties

Luster

Vitreous, Resinous
Vitreous

Pleochroism

-
Weak: yellowish brown yellowAnthony et al

Dispersion

0.020.01
0.005 1
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Transparency

-
-

Refractive Index

1.546-1.5481.509-1.541
1 3.25
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Optic Character

-
-

Crystal System

Triclinic
-

Birefringence

0.0210.030
0 0.296
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Clarity

-
TransparentUlrich Henn and Claudio C. Milisenda

Polyhalite and Mellite Optic Character

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

Polyhalite and Mellite Transparency

Similar to their colors, Polyhalite and Mellite 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, Polyhalite is while Polyhalite is in appearance.