TWI357438B

Polishing particles are made of artificial diamond produced by a shock method, having density of 3.0-3.35 g/cm3 and including secondary particles with average particle diameter of 30 nm-500 nm. Such polishing particles are produced by firstly obtaining a product containing artificial diamond by a shock method, then subjecting this product to an acid treatment by using one or more strong acids such as concentrated sulfuric acid, concentrated nitric acid and concentrated hydrochloric acid to thereby remove impurities from and wash the product, thereafter subjecting the product to a classification process to thereby separate artificial diamond of a first kind having secondary particles with particle diameters of 30 nm-500 nm and artificial diamond of a second kind having secondary particles with particle diameters in excess of 500 nm and selecting artificial diamond of a third kind having density of 3.0-3.35 g/cm3 out of the artificial diamond of the first kind. It is the artificial diamond of the third kind tha