Formula: BaNa4Ti2NbSi4O17(F,OH) . Na3PO4
Reflected/transmitted colour: colourless to brownish
Pleochroism: weak, a = b = colourless, g = brownish
Optical isotropy/anisotropy: biaxial
Optical sign: +
Refractive indices: a = 1.682-1.683, b = 1.687-1.695, g = 1.718-1.720
Birefringence δ: 0.038
2V angle: 40° (measured) 66° (calculated)
Dispersion:
Optical orientation: a = c, b = b, g = a
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 |