Tourmaline and Petalite Optical Properties

Tourmaline

Petalite

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1 Optical Properties

1.1 Luster

Vitreous

Vitreous, Pearly

1.2 Pleochroism

typically moderate to strong

AbsentWalter Schumann

1.3 Dispersion

0.020.01

0.007 1

1.4 Transparency

Transparent, Translucent, Transparent to opaque

Gemmological Tables (2004) More from other references

1.5 Refractive Index

1.614-1.6661.502-1.523

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Trigonal

monoclinic

1.8 Birefringence

0.014-0.0400.012-0.016

0 0.296

1.9 Clarity

Transparent

TransparentUlrich Henn and Claudio C. Milisenda

Tourmaline and Petalite Optic Character

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

Similar to their colors, Tourmaline and Petalite 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.