Spectrum Normalized Raman spectrum of $SiO_2$ quartz acquired with a 514 nm laser Spectrum Normalized Raman spectrum of $SiO_2$ coesite acquired with a 514 nm laser Spectrum Normalized Raman spectrum of $SiO_2$ cristobalite acquired with a 514 nm laser Spectrum Normalized Raman spectrum of $SiO_2$ stishovite acquired with a 514 nm laser Spectrum Normalized Raman spectrum of $SiO_2$ tridymite acquired with a 514 nm laser