Varadway and coworkers used a Renishaw Raman System 1000B and a laser at 514 nm. "Most of the Raman studies on bulk iron oxides have been on Fe3O4 and α-Fe2O3". In magnetite we have five Raman bands, but in "earlier studies only four bands at 193, 306, 538 and 668 cm -1 are observed" (Varadway et al., mentioning Shebanova and Lazor). For α-Fe2O3, seven "phonon lines are expected at 225, 247, 293, 299, 412, 498 and 613 cm -1 . In addition to these bands an intense band at 1320 cm -1 is observed due to a two magnon scattering". The γ-Fe2O3 has a Raman spectrum characterized by three broad bands around 350, 500 and 700 cm -1 , not present in the spectrum of any iron oxide or oxyhydroxide.