Adobe

Adobe soil, often referred to as clay soil, is a naturally occurring substance made up mostly of fine-grained minerals that are pliable through a wide range of water contents and that can be made harder by drying and/or firing. Clay minerals, such as phyllosilicate minerals, lend flexibility and harden when burnt and/or dried, and varying amounts of water trapped in the mineral structure by polar attraction make up the majority of clay deposits. Clay deposits may also contain organic elements that lack flexibility.