Formula: K2(Li,Al)5-6(Si6-7Al2-1O20)(OH,F)4
Reflected/transmitted colour: colourless
Pleochroism: absorption greater for vibration directions in the plane of cleavage
Optical isotropy/anisotropy: biaxial
Optical sign: -
Refractive indices: α = 1.524-1.548, β = 1.543-1.588, γ = 1.545-1.587
Birefringence δ: 0.018-0.038
2Vα angle: 0-58°
Dispersion: r > v
Optical orientation: β = y, γ Λ x = 0-7°
Optical axial plane: (010)
| 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 |