Foitite and Demantoid Optical Properties

Foitite

Demantoid

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1 Optical Properties

1.1 Luster

Vitreous

Adamantine

1.2 Pleochroism

Strong: pale lavender dark blueAnthony et al

None

1.3 Dispersion

NANA

0.007 1

1.4 Transparency

TranslucentAnthony et al, Translucent

Gemmological Tables (2004)

1.5 Refractive Index

Not Available1.880-1.890

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

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

cubic

1.8 Birefringence

Not AvailableNot Available

0 0.296

1.9 Clarity

TranslucentAnthony et al

TransparentUlrich Henn and Claudio C. Milisenda

Foitite and Demantoid Optic Character

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

Similar to their colors, Foitite and Demantoid 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.