PURPOSE: To provide an abrasive grain which easily forms hard sharp edges contributing to grinding and has excellent grinding performance by impregnating porous alumina obtained by calcining an alumina gel with a silicon compound and a carbon compound, drying the product of impregnation and sintering the dried product in a nitrogen atmosphere.

CONSTITUTION: Porous alumina obtained by calcining an alumina gel is impregnated with a silica compound and a carbon compound, the product of impregnation is dried, and the dried product is sintered while it is being nitrided in a nitrogen or ammonia atmosphere to produce the objective grains. Examples of the silicon compounds includes silicon tetrachloride, tetraethoxysilane, silica, etc. Examples of the carbon compounds include saccharides such as sucrose and glucose and resins such as polyvinyl alcohol and phenolic resins.