Abstract: A wire is used to cut or slice diamond by passing the wire rapidly and under light load over and into the diamond surface along a line to be cut. In one form of the invention, the wire comprises a metal that dissolves diamond, such as iron or nickel and the wire and/or diamond is preferably heated to approach the metal-carbon eutectic temperature and create sensible reaction rates of the carbon on the wire surface. In another form of the invention, the moving wire carries a molten oxidant to enhance the cutting rate. The molten oxidant may be, for example, sodium nitrate, which oxidizes carbon.