Formula: Ca2Al4(Si4Al4O20)(OH)4
Reflected/transmitted colour: colourless
Pleochroism: very weak or absent
Optical isotropy/anisotropy: biaxial
Optical sign: -
Refractive indices: α = 1.630-1.638, β = 1.642-1.648, γ = 1.644-1.650
Birefringence δ: 0.012-0.014
2Vα angle: 40-67°
Dispersion: r < v
Optical orientation: β Λ x = 6-8°, γ = y
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 |