Single-cutter experiments have been performed to investigate the cutting and wear of thermally stable diamond (SYNDAX3) during rock cutting. Cutting forces increase linearly with depth of cut, but are unaffected by cutting speed. The wear of the cutter per mass of rock removed is found to decrease with increasing depth of cut. Excessive cutting speed is harmful to the cutter since both the cutter temperature and the change in cutter temperature per power input increase with cutting speed. In the cutting experiments, evidence of delayed fracturing is observed. For essentially constant cutting conditions, fractures develop in the cutter only after a significant amount of cutting is done. Damage of this type is very harmful to the cutter as cutter temperature rises and efficiency drops with increasing wear.