Zoisite and Allanite Optical Properties

Zoisite

Allanite

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1 Optical Properties

1.1 Luster

Vitreous

Not Available

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.

Not Available

1.5 Refractive Index

1.685-1.7071

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Orthorhombic

Not Available

1.8 Birefringence

0.006-0.0180.013-0.036

0 0.296

1.9 Clarity

Transparent

Not Available

Zoisite and Allanite Optic Character

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

Similar to their colors, Zoisite and Allanite 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.