Thulite and Covellite Optical Properties

Thulite

Covellite

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1 Optical Properties

1.1 Luster

Vitreous

Resinous

1.2 Pleochroism

Present

Marked

1.3 Dispersion

NANA

0.007 1

1.4 Transparency

Opaque, Translucent, Opaque . May be translucent in thin backlit sections.

OpaqueAnthony et al, Handbook of mineralogy (2001) More from other references

1.5 Refractive Index

1.6951.45-2.62

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Orthorhombic

Hexagonal

1.8 Birefringence

0.006-0.018Not Available

0 0.296

1.9 Clarity

OpaqueHerve Nicolas Lazzarelli

OpaqueAnthony et al

Thulite and Covellite Optic Character

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

Similar to their colors, Thulite and Covellite 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, Thulite is Opaque, Opaque . May be translucent in thin backlit sections. and Translucent while Thulite is Opaque, Opaque . May be translucent in thin backlit sections. and Translucent in appearance.