Experimental investigations on the comminution of fused corundum and silicon carbide show that comminution and wear behaviour of ceramic grinding beads are affected by the structural constitution of grinding beads. For grinding beads composed of large primary particles, the achievable product fineness seems to be limited by the size of the primary particles. For the grinding beads composed of small primary particles, the product fineness is not limited by the size of the primary particles. The relation between specific energy requirement and product fineness is essentially affected by the amount of grinding bead wear. The wear of grinding beads is determined by the structure and the hardness of beads as well as by the hardness and the shape of the feed particles.