Felbertalite

Formula: Cu₂Pb₆Bi₈S₁₉

Reflected/transmitted colour: White

Pleochroism:

Optical isotropy/anisotropy: Distinct anisotropic

Optical sign:

Refractive indices:

Bireflectance/Birefringence δ: Perceptible in air, more noticable in oil.

2V angle:

Dispersion:

Optical orientation:

Optical axial plane:

Felbertalite (with light brownish and blue tarnishing colours) and lillianite (light grey). Polished section (from microprobe analysis) in reflected light.

Origin: Scheelite deposit, Felben valley, Hohe Tauern Mts, Salzburg, Austria

Picture size: 0.7 mm

Owner: Thomas Witzke

 

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