Dravite and Bertrandite Optical Properties

Dravite

Bertrandite

Add ⊕

1 Optical Properties

1.1 Luster

Vitreous

1.2 Pleochroism

Very strong: pale yellow colorless

none.

1.3 Dispersion

0.02NA

0.007 1

1.4 Transparency

Transparent

TransparentAnthony et al, Handbook of mineralogy (2001)

1.5 Refractive Index

1.614-1.6661.583-1.614

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

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

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

1.8 Birefringence

0.014-0.032Not Available

0 0.296

1.9 Clarity

Transparent

TransparentAnthony et al

Dravite and Bertrandite Optic Character

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

Compare Blue Gemstones

Dravite Vs Fluorite

Dravite Vs Gahnite

Dravite Vs Gadolinium Gallium Garnet

Dravite and Bertrandite Transparency

Similar to their colors, Dravite and Bertrandite 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, Dravite is Transparent while Dravite is Transparent in appearance.