Bertrandite and Danburite Optical Properties

Bertrandite

Danburite

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1 Optical Properties

1.1 Luster

Vitreous

Vitreous, Greasy

1.2 Pleochroism

none.

Weak: pale yellow yellow

1.3 Dispersion

NA0.02

0.007 1

1.4 Transparency

TransparentAnthony et al, Handbook of mineralogy (2001)

Gemmological Tables (2004) More from other references

1.5 Refractive Index

1.583-1.6141.627-1.639

1 3.25

1.6 Optic Character

Not Available

Biaxial/+

1.7 Crystal System

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

Orthorhombic

1.8 Birefringence

Not Available0.006

0 0.296

1.9 Clarity

TransparentAnthony et al

TransparentUlrich Henn and Claudio C. Milisenda

Bertrandite and Danburite Optic Character

Bertrandite and Danburite optical properties play a significant role while distinguishing these gemstones from each other. These properties are influenced by the Bertrandite and Danburite 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 Danburite 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. Danburite has Biaxial/+ character.

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Bertrandite and Danburite Transparency

Similar to their colors, Bertrandite and Danburite 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.