Tanzanite and Alexandrite Optical Properties

Tanzanite

Alexandrite

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1 Optical Properties

1.1 Luster

Vitreous

1.2 Pleochroism

Present

Not Available

1.3 Dispersion

0.03NA

0.007 1

1.4 Transparency

Transparent, Translucent, Transparent to translucent

Transparent, Transparent to nearly opaque

1.5 Refractive Index

1.685-1.7071.739-1.770

1 3.25

1.6 Optic Character

Not Available

Biaxial/+

1.7 Crystal System

Orthorhombic

1.8 Birefringence

0.006-0.0180.007-0.010

0 0.296

1.9 Clarity

TransparentUlrich Henn and Claudio C. Milisenda

Transparent

Tanzanite and Alexandrite Optic Character

Tanzanite and Alexandrite optical properties play a significant role while distinguishing these gemstones from each other. These properties are influenced by the Tanzanite and Alexandrite 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 Tanzanite and Alexandrite 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. Alexandrite has Biaxial/+ character.

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Tanzanite and Alexandrite Transparency

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