This is copper and dates back to about 1900. It may not look like a dolphin but this is what it is. This is copper lined with tin on the inside. Some of the earliest chocolate molds were made with copper. The detail on this is just exquisite. Stamped 120 on one side of the mold. About 6 inches tall and 3 1/2 inches wide. Has a lot of patina and verdigris. Inside is lined with tin and has a few small rust spots.