Franconite

Formula: Na2Nb4O11 . 9H2O

Reflected/transmitted colour: Colourless

Pleochroism:

Optical isotropy/anisotropy: Biaxial

Optical sign: -

Refractive indices: α = 1.720, β = 1.780, γ = 1.790

Bireflectance/Birefringence δ: 0.070

2V angle:

Dispersion:

Optical orientation:

Optical axial plane:

 

Back to Alphabetical list Colour photos Physical, chemical and crystallographic description SEM images TEM images vibrational spectra description IR spectra Raman spectra N-IR spectra F-IR spectra IES spectra