Formula: Al12(SO4)5(OH)26. 20H2O
Reflected/transmitted colour:
Pleochroism:
Optical isotropy/anisotropy: Biaxial
Optical sign: +
Refractive indices: α = 1.498, β = 1.4981, γ = 1.499
Bireflectance/Birefringence δ: 0.001
2V angle: 38° (calculated), moderate (measured)
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 |