Spectrum Normalized Raman spectrum of $Al_2O_3$ corundum acquired with a 532 nm laser Spectrum Normalized Raman spectrum of $\alpha-Fe_2O_3$ hematite acquired with a 514 nm laser Spectrum Normalized Raman spectrum of $Fe_3O_4 (Fe^{2+} Fe_2^{3+} O_4)$ magnetite acquired with a 514 nm laser Spectrum Normalized Raman spectrum of $TiO_2$ rutile acquired with a 514 nm laser Spectrum Normalized Raman spectrum of $TiO_2$ anatase acquired with a 532 nm laser Spectrum Normalized Raman spectrum of $\alpha - Fe^{3+}O(OH)$ goethite acquired with a 532 nm laser Spectrum Normalized Raman spectrum of $MgTiO_3$ geikielite acquired with a 514 nm laser Spectrum Normalized Raman spectrum of $(Ba,H_2O)_2(Mn^{4+},Mn^{3+})_5O_{10}$ romanechite acquired with a 532 nm laser Spectrum Normalized Raman spectrum of $Mg(OH)_2$ brucite acquired with a 532 nm laser