Abstract: A method for evaluating the quality of abrasive grains for polishing glass, which comprises adding abrasive grains to be measured, to an aqueous medium having silica dissolved therein, to have the silica adsorbed on the abrasive grains under such a condition that the silica undergoes substantially no polymerization in the aqueous medium, followed by solid-liquid separation to separate the abrasive grains from the mother liquor, and measuring the concentration of silica remaining in the mother liquor to measure the adsorption rate (?) of silica on the abrasive grains.

Abstract: A method for evaluating the quality of abrasive grains for polishing glass, which comprises adding abrasive grains to be measured, to an aqueous medium having silica dissolved therein, to have the silica adsorbed on the abrasive grains under such a condition that the silica undergoes substantially no polymerization in the aqueous medium, followed by solid-liquid separation to separate the abrasive grains from the mother liquor, and measuring the concentration of silica remaining in the mother liquor to measure the adsorption rate (&eegr;) of silica on the abrasive grains.

Abstract: An abrasive for planarization of glass substrates for hard discs comprising abrasive grains mainly composed of rare earth oxides containing cerium oxide, wherein the abrasive grains has a cerium oxide/total rare earth oxide ratio of 95 wt %.

Abstract: An abrasive comprising at least the following components (A) and (B): (A) cerium-containing abrasive grains having an average particle size of from 0.5 to 5.0 &mgr;m; and (B) particles having an average particle size of from 0.01 to 0.3 &mgr;m, which are particles of at least one member selected from the group consisting of aluminum oxide, silicon dioxide, zirconium oxide, titanium oxide, silicon nitride and manganese oxide.