Omphacite and Sillimanite Optical Properties

Omphacite

Sillimanite

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1 Optical Properties

1.1 Luster

Vitreous

Vitreous, Subadamantine, Silky

1.2 Pleochroism

Weak: colorless -- very pale green -- very pale green

Colourless to pale brown to yellow

1.3 Dispersion

NANA

0.007 1

1.4 Transparency

TranslucentAnthony et al, Handbook of mineralogy (2001)

Transparent, Translucent

1.5 Refractive Index

1.662-1.7231.653-1.685

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Not Available

Orthorhombic

1.8 Birefringence

Not Available0.020-0.022

0 0.296

1.9 Clarity

TranslucentAnthony et al

Transparent

Omphacite and Sillimanite Optic Character

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

Similar to their colors, Omphacite and Sillimanite 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, Omphacite is Handbook of mineralogy (2001) and TranslucentAnthony et al while Omphacite is Handbook of mineralogy (2001) and TranslucentAnthony et al in appearance.