Bergman, M. Powder data fie as a tool for identification of dental gold alloys.In order to obtain data for a prospective powder data file for dental gold alloys X-ray diffraction photograms of 75 different gold alloys were taken using a Guinier-Hägg camera and CuKα1radiation. Before the X-ray photograms were taken the alloys had been heat treated at 700°C, 800°C or 900°C depending on the solidus temperatures of the alloys. The lattice parameters of the samples were determined from the X-ray photograms. These data were supplemented by a specification of the mterplanar spacings of the three strongest lines on the diffraction patterns and also by the relath intensities and Miller indices of these lines. An extensive library of reference films is to be collected and this and other details of the file are discussed. It is not intended that the file be used to identify a particular alloy but merely to identify the type of alloy. Thus it can serve as a guide to facilitate the proper selection of gold alloys within practical clinical dentistry.