They are red clay pans that are fired, then glazed and fired again. They are typically made in Italy, France and Spain -- I am not sure if you can find them from Asia (yet).
Here is a link that describes the ones we sell in the FB Store. That should be helpful. Our pans are made in Tuscany, and have either a nice green or blue glaze.
James
http://www.fornobravo.com/forum/f18/...tails-560.html (Terracotta bakeware details)