Variations in the grinding (machining) properties of aluminum oxide attributable to the Rebinder effect, an environment-caused variation in the hardness of rock, ceramic, or glass, were investigated using conventional surface grinding equipment. Systematic variation in normal force, tangential force, roughness average, waviness average, and post grinding flexural strength were attributable to the grinding condition (coarse or fine) and the pH of the coolant. Observations in this study are consistent with a ductile/brittle grinding transition for fine grinding, a brittle/brittle grinding transition for coarse grinding and pH control of plastic deformation. (C) 2003 Kluwer Academic Publishers.