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PROBLEM TO BE SOLVED : To provide a cerium-based abrasive with reduced content of thorium (Th), uranium (U), or the like, having high polishing rate equivalent to or higher than conventional abrasives.
SOLUTION : In this cerium-based abrasive that contains fluorine, the mass ratio in terms of total rare earth oxides (TREO) relative to the mass of the abrasive accounts for ≥90 wt.%, the mass ratio of the total content of Th and U relative to TREO ((Th+U)/TREO) accounts for ≤0.05 wt.%, and the average particle diameter (DB) determined by the Blaine method falls in the range of 1.5-2.5 μm. In this cerium-based abrasive wherein the particle diameter is set based on DB, abrasive particle diameter distribution is controlled for achieving a required polishing rate. The use of DB as the particle diameter setting standard in the cerium-based abrasive manufacturing process decreases the content of Th, U, or the like, but increases the polishing rate.