In Ogorodova et al., 2017, we can find in the Figure a Raman spectrum of vivianite. "Raman spectroscopic study was carried out on a Raman microscope EnSpectr R532 (Russia) with a diffraction grating (1800 lines/mm) and a spectral resolution of about 6 cm -1 . The laser radiation wavelength was equal to 532 nm, the laser radiation power on the sample was approximately 15 mW, … Spectrum was obtained on a non-oriented single crystal". "Anion [PO4] 3-is manifested in the spectrum by a group of lines: a strong line at 950 cm -1 corresponds to the totally symmetric valence vibration of the anion; a weak line at 1055 cm -1 relates to the triply degenerate antisymmetric valence vibration; the lines at 539 and 572 cm -1 belong to the triply degenerate deformation vibration; a line near 458 cm -1 corresponds to doubly degenerate deformation vibration of tetrahedra [PO4] 3-. The high-frequency line with maximum at 3138 cm -1 and shoulder near 3280 cm -1 correspond to the valence vibrations of OH-groups (in water molecules). A weak line with maximum near 3475 cm -1 relates to valence vibrations of OH-groups in the coordination Fe 3+ OH" (Ogorodova et al., mentioning ).