Clay is a material that is mechanically strong and can be given the desired shape easily. Mugs and other products made with clay have a long life as compared to mugs made of glass. Also, clay can be given any shape easily, that makes it possible to have different designs.
The oldest mugs were discovered in China and Japan, by archeologists dating back to the Neolithic Stone Age, some 10,000 years B.C. The drinking vessels, found were durable yet lacked handles.