Cemented WC-Co composites were abraded by quartz abrasives in a three-body test. It was found that the quartz has an effective hardness as an abrasive of 1260–1320 kg/mm2 (12.36–12.94 GPa), which makes it a soft abrasive relative to most cemented carbides. Material is removed in abrasive wear by two mechanisms—cobalt extrusion and carbide fragmentation. The binder extrusion is rate-controlling and occurs due to repeated loading of the surface material in friction-generated shear. The cracking and fragmentation of the carbide grains is a secondary removal mechanism which depends upon the relaxation of compressive stresses in the carbide grains as the cobalt binder is extruded. The wear rate is directly related only to binder mean free path and it increases linearly with this parameter.