Zoisite and Alexandrite Optical Properties

Zoisite

Alexandrite

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1 Optical Properties

1.1 Luster

Vitreous

1.2 Pleochroism

X = pale pink to red-violet; Y = nearly colorless to bright pink or deep blue; Z = pale yellow to yellow-green

Not Available

1.3 Dispersion

0.02NA

0.007 1

1.4 Transparency

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

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

Transparent

Zoisite and Alexandrite Optic Character

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

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