Electrofused alumina grains comprising zirconium and at least either one of tungsten or molybdenum, wherein the total of a tungsten content in terms of WO 3 and a molybdenum content in terms of MoO 3 is 0.05 to 3.00% by mass, and satisfying the following expression: y < − 1.506 x + 3.605 wherein x represents the C-stage bulk specific gravity of the electrofused alumina grains, as determined in accordance with JIS R6126-1970 using an apparatus composed of a funnel, a stopper, and a cylinder and a support therefor by the following process: the volume V (ml) of the cylinder was measured; the outlet port of the funnel was plugged with a stopper, about 120 ml of a sample was placed into the funnel, and the cylinder was disposed immediately below the funnel; the stopper was withdrawn to drop the total amount of the sample down into the cylinder, the sample banked up on the top of the cylinder was removed by lightly scooping it, and then the weight of the sample put in the cylinder was measured; the operation of and was repeated for the same sample to obtain three measured values: W1 (g), W2 (g), and W3 (g); from the volume V (ml) of the cylinder obtained in, and the three measured values: W1 (g), W2 (g), and W3 (g) obtained in, the C-stage bulk specific gravity was calculated by the following expression: C-Stage Bulk Specific Gravity g / ml = W 1 + W 2 + W 3 / 3 / V and wherein y represents the C-coefficient of the electrofused alumina grains, as determined by a method wherein, using a standard sieve specified in JIS R6001-1987, 250 g of electrofused alumina grains were sieved by a ro-tap tester for 10 minutes; the total amount of the sample remaining on the 3rd stage sieve was further sieved for 10 minutes, and 100 g of the electrofused alumina grains remaining again on the 3rd stage sieve was used as a test sample; the test sample was ground with a ball mill by the method specified in JIS R6128-1975 to prepare a ground sample; the ground sample was sieved using a standard sieve for 5 minutes, and the weight of the ground sample remaining on the 4th sieve was referred to as R (x); as a standard sample, a black silicon carbide abrasive F 60 specified in JIS R6128-1975 was subjected to the same operation as above, and after grinding with a ball mill, the weight of F60 remaining on the 4th stage sieve was referred to as R(s); the C-coefficient was calculated by the following expression: C-coefficient = log 100 / R x / log 100 / R s the volume V (ml) of the cylinder was measured; the outlet port of the funnel was plugged with a stopper, about 120 ml of a sample was placed into the funnel, and the cylinder was disposed immediately below the funnel; the stopper was withdrawn to drop the total amount of the sample down into the cylinder, the sample banked up on the top of the cylinder was removed by lightly scooping it, and then the weight of the sample put in the cylinder was measured; the operation of and was repeated for the same sample to obtain three measured values: W1 (g), W2 (g), and W3 (g); from the volume V (ml) of the cylinder obtained in, and the three measured values: W1 (g), W2 (g), and W3 (g) obtained in, the C-stage bulk specific gravity was calculated by the following expression: C-Stage Bulk Specific Gravity g / ml = W 1 + W 2 + W 3 / 3 / V and wherein y represents the C-coefficient of the electrofused alumina grains, as determined by a method wherein, using a standard sieve specified in JIS R6001-1987, 250 g of electrofused alumina grains were sieved by a ro-tap tester for 10 minutes; the total amount of the sample remaining on the 3rd stage sieve was further sieved for 10 minutes, and 100 g of the electrofused alumina grains remaining again on the 3rd stage sieve was used as a test sample; the test sample was ground with a ball mill by the method specified in JIS R6128-1975 to prepare a ground sample; the ground sample was sieved using a standard sieve for 5 minutes, and the weight of the ground sample remaining on the 4th sieve was referred to as R (x); as a standard sample, a black silicon carbide abrasive F 60 specified in JIS R6128-1975 was subjected to the same operation as above, and after grinding with a ball mill, the weight of F60 remaining on the 4th stage sieve was referred to as R(s); the C-coefficient was calculated by the following expression: C-coefficient = log 100 / R x / log 100 / R s