Astrophyllite and Bertrandite Optical Properties

Astrophyllite

Bertrandite

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1 Optical Properties

1.1 Luster

Greasy, Pearly

Vitreous

1.2 Pleochroism

Strong: X= deep red-orange Y= orange-yellow Z= lemon-yellow

none.

1.3 Dispersion

NANA

0.007 1

1.4 Transparency

Translucent

TransparentAnthony et al, Handbook of mineralogy (2001)

1.5 Refractive Index

1.678-1.7581.583-1.614

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Triclinic

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

1.8 Birefringence

0.050Not Available

0 0.296

1.9 Clarity

Translucent

TransparentAnthony et al

Astrophyllite and Bertrandite Optic Character

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

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Astrophyllite and Bertrandite Transparency

Similar to their colors, Astrophyllite 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, Astrophyllite is Translucent while Astrophyllite is Translucent in appearance.