Tourmaline and Covellite Optical Properties

Tourmaline

Covellite

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1 Optical Properties

1.1 Luster

Vitreous

Resinous

1.2 Pleochroism

typically moderate to strong

Marked

1.3 Dispersion

0.02NA

0.007 1

1.4 Transparency

Transparent, Translucent, Transparent to opaque

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

1.5 Refractive Index

1.614-1.6661.45-2.62

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Trigonal

Hexagonal

1.8 Birefringence

0.014-0.040Not Available

0 0.296

1.9 Clarity

Transparent

OpaqueAnthony et al

Tourmaline and Covellite Optic Character

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

Similar to their colors, Tourmaline 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, Tourmaline is Translucent, Transparent and Transparent to opaque while Tourmaline is Translucent, Transparent and Transparent to opaque in appearance.