Formula: KAl2(Si3B)O10(OH,F)2
Reflected/transmitted colour:
Pleochroism:
Optical isotropy/anisotropy: biaxial
Optical sign: -
Refractive indices: a = 1.557, b = 1.587, g = 1.593
Birefringence δ: 0.035
2V angle: 47.5°
Dispersion: r > v, weak
Optical orientation: a Ù c = -1°, b Ù a = 2°, g = b
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 |