Diamond has been found to grow from copper, zinc, and germanium when temperatures and pressures in excess of those usually used for growth via conventional catalysts are used. Around their melting temperatures these metals are inert with respect to graphite. However, under the conditions used in this study, namely temperatures of 1600 °C and pressures of 6 GPa, they exhibit catalytic action. The conventional catalysts, which were first discovered by General Electric, act as catalysts immediately after melting in the presence of graphite, and this distinguishes them from the catalysts used in this study which should therefore be placed in a different category. A new model of diamond growth is proposed in order to explain the behavior of these new catalysts.