Sillimanite and Precious Opal Optical Properties

Sillimanite

Precious Opal

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1 Optical Properties

1.1 Luster

Vitreous, Subadamantine, Silky

Not Available

1.2 Pleochroism

Colourless to pale brown to yellow

AbsentWalter Schumann

1.3 Dispersion

NANone

0.007 1

1.4 Transparency

Transparent, Translucent

1.5 Refractive Index

1.653-1.6851.370-1.470

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Orthorhombic

Not Available

1.8 Birefringence

0.020-0.022Not Available

0 0.296

1.9 Clarity

Transparent

Sillimanite and Precious Opal Optic Character

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

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Sillimanite and Precious Opal Transparency

Similar to their colors, Sillimanite and Precious 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, Sillimanite is Translucent and Transparent while Sillimanite is Translucent and Transparent in appearance.