Abstract: A reinforced ceramic structure, such as a superplastic forming die for forming a metal part, has a body of cast silica/calcium aluminate or mullite based ceramic material; and a plurality of reinforcing rods, made of monolithic fused oxides of silicon or aluminum, cast into said ceramic body. The rods have a thickness between ⅛″-2.0″ and are spaced apart on centers by about 2-10 times the diameter of the rods. The rods are bonded in the ceramic body or they may be coated with a release agent to prevent bonding to said ceramic body so that they can translate in the direction of their axes to prevent cracking during drying and curing. The rods are disposed in an array of at least two rows, with the rods in each row arranged parallel to each other and with the rods in adjacent rows arranged orthogonally to each other. The rows are spaced apart a distance equal to about ½-3 times the diameter of the rods.