Abstract: During grinding and polishing of an optical element made of a crystalline material such as fluorite, tarnish and a reaction with diamond polishing abrasive grains included in processing liquid are prevented. To this end, processing liquid supplied to a processing region of a surface to be processed and processing liquid supplied to a non-processing region are divided.

Abstract: A brittle-material machining method and apparatus achieves grinding in a ductile mode region using an ordinary grinding apparatus. Grinding or polishing of a workpiece consisting of a brittle material is performed by relative movement between the workpiece and a grinding wheel, which includes innumerable abrasive grains provided on a support base, while the grinding wheel is brought into pressured contact with the workpiece at a prescribed pressure. The grinding or polishing is carried out upon setting the prescribed pressure in such a manner that depth of cut d, into the workpiece, of abrasive grains among the innumerable number thereof that participate in the grinding or polishing is made less than a critical depth of cut d.sub.c, which is a minimum depth of cut at which brittle fracture is produced in the workpiece.

Abstract: Disclosed is a precise grinding grindstone in which the-heights of the grinding particles can be aligned even if large particles are employed. An underlying plated layer is formed on a substrate, and grinding particles are dispersed as a single layer thereon. The grinding particles are pressed toward the plated layer by a mold member and are partly pressed into the plated layer, whereby the heights of the grinding particles are aligned. Then, the particles are supported by a binding plated layer. The protrusion of the particles can be arbitrarily selected by regulating the thickness of the binding plated layer.