Spinel and Petalite Optical Properties

Spinel

Petalite

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1 Optical Properties

1.1 Luster

Vitreous

Vitreous, Pearly

1.2 Pleochroism

Absent

AbsentWalter Schumann

1.3 Dispersion

0.020.01

0.007 1

1.4 Transparency

Transparent, Translucent, Transparent to translucent

Gemmological Tables (2004) More from other references

1.5 Refractive Index

1.731.502-1.523

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Isometric

monoclinic

1.8 Birefringence

Not Available0.012-0.016

0 0.296

1.9 Clarity

TransparentUlrich Henn and Claudio C. Milisenda

Spinel and Petalite Optic Character

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

Similar to their colors, Spinel 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, Spinel is Translucent, Transparent and Transparent to translucent while Spinel is Translucent, Transparent and Transparent to translucent in appearance.