FOUND & Co. The Roseville Blue Sponge BowlAuthentic Roseville USA pottery in classic cobalt sponge glaze. A genuine Roseville USA art pottery bowl featuring a rich cobalt blue spongeware glaze over warm cream stoneware. Stamped on the base R. R. P. Co. Roseville U. S. A., this 4 inch diameter, 2 inch tall piece was produced by Robinson Ransbottom Pottery Company of Roseville, Ohio known for its durable American stoneware and spongeware designs. The hand applied cobalt sponge pattern gives