Formula: (Mn,Mg)5(SiO4)2(OH)2
Reflected/transmitted colour:
Pleochroism:
Optical isotropy/anisotropy: Biaxial
Optical sign: +
Refractive indices: α = 1.78, β = 1.792, γ = 1.808
Bireflectance/Birefringence δ: 0.028
2V angle: 84° (calculated), 83° (measured)
Dispersion:
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 |