Sea ceramic originates from pottery, including earthenware, stoneware and porcelain which breaks into smaller pieces and is smoothed by the acidity and motion of an ocean, the sand or grit polishes the edges like a natural tumbler. Much of the sea ceramic here in the United States originated from discarded 18th and 19th century porcelain made in Europe and America. Some sea ceramic contains discernible patterns, such as flowers, figures, historic places and scenes.