Question: what is the difference between stoneware and earthenware clay?
Answer: It depends largely on how porous the unglazed, but fired, piece is. If it has more than 5% porosity, then it's earthenware. If it's less porous, but not quite 0%, it's stoneware. If the fired clay body is totally vitreous, with 0% porosity, is considered porcelain.