typically react with alumina to form a garnet beta alumina perovskite or hexagonal rare earth aluminate crystal structure the average particle size of the fines should initially be between about 0 05 and 50 micrometers the average particle size of the non sintered particle is between 50 micrometers to 1200 micrometers in general the large particle size fines do not work as well as the small particle fines on the small particle size non sintered particles for example an abrasive grain having a particle size of 120 micrometers typically would have fines on the order of 0 2 to 5 micrometers likewise an abrasive grain having a particle size of 600 micrometers preferably has fines on the order of 0 2 to 10 micrometers the preferred addition fine average particle size is between 0 1 and 15 micrometers if the particle size of the fines is too large adhesion to the surface of the abrasive grain may be inadequate if the particle size of the fines is too small there would be little or no increase in surface area the ceramic abrasive grains of the present invention are conveniently handled and incorporated into various abrasive products according to well known techniques to make for example coated abrasive products bonded abrasive products and lofty non woven abrasive products the methods of making such abrasive products are well known to those skilled in the.