Bertrandite and Demantoid Optical Properties

Bertrandite

Demantoid

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1 Optical Properties

1.1 Luster

Vitreous

Adamantine

1.2 Pleochroism

none.

None

1.3 Dispersion

NANA

0.007 1

1.4 Transparency

TransparentAnthony et al, Handbook of mineralogy (2001)

Gemmological Tables (2004)

1.5 Refractive Index

1.583-1.6141.880-1.890

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Orthorhombic Pyramidal H-M Symbol (mm2) Space Group: Ccm21

cubic

1.8 Birefringence

Not AvailableNot Available

0 0.296

1.9 Clarity

TransparentAnthony et al

TransparentUlrich Henn and Claudio C. Milisenda

Bertrandite and Demantoid Optic Character

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

Similar to their colors, Bertrandite 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, Bertrandite is Handbook of mineralogy (2001) and TransparentAnthony et al while Bertrandite is Handbook of mineralogy (2001) and TransparentAnthony et al in appearance.