Summary: Oxides of the Cu-Fe-O system prepared by solid-state reaction methods have been investigated by X-ray, Mössbauer effect, and analytical chemical techniques. In agreement with most previous investigations of this system, it is found that CuFeO₂ exists as a stable compound, and that the mineral delafossite has essentially this composition. These results are in disagreement with those of Buist, Gadalla, and White who propose that delafossite has an approximate composition Cu₆Fe₃O₇ instead of CuFeO₂. In fact, a compound of composition Cu₆F₃O₇ could not be prepared. The Mössbauer isomer shift provides confirmation that the iron in CuFeO₂ is trivalent.