Foitite and Allanite Optical Properties

Foitite

Allanite

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1 Optical Properties

1.1 Luster

Vitreous

Not Available

1.2 Pleochroism

Strong: pale lavender dark blueAnthony et al

Not Available

1.3 Dispersion

NANA

0.007 1

1.4 Transparency

TranslucentAnthony et al, Translucent

Not Available

1.5 Refractive Index

Not Available1

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Trigonal Ditrigonal Pyramidal H-M Symbol (3m) Space Group: R 3m

Not Available

1.8 Birefringence

Not Available0.013-0.036

0 0.296

1.9 Clarity

TranslucentAnthony et al

Not Available

Foitite and Allanite Optic Character

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

Similar to their colors, Foitite 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, Foitite is Translucent and TranslucentAnthony et al while Foitite is Translucent and TranslucentAnthony et al in appearance.