Formula: NaCaMn3Si5O14(OH)
Reflected/transmitted colour:
Pleochroism:
Optical isotropy/anisotropy: Biaxial
Optical sign: +
Refractive indices: α = 1.686, β = 1.691, γ = 1.708
Bireflectance/Birefringence δ: 0.022
2V angle: 58 (calculated), 60 (measured)
Dispersion: Weak, r > v
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 |