1. A native earth consisting mainly of decomposed feldspathic rock (feldspathic: grouping of crystalline minerals that consist of aluminum silicates with either potassium, sodium, calcium or barium) containing kaolin and other hydrous aluminous minerals. Becomes hard when baked or fired. See Terra cotta. Used wet by the sculptor to build or model the form, often over an armature of wood or metal: it is then called wet clay - as compared with what is often called modelling clay 2. Sold under various names such as Plasticine and Plastilina, originally made in Italy with tallow, sulphur and high-quality clay. Also made less expensively with clay, an inert filler and various petroleum oils and greases heated and thoroughly mixed - can be variously coloured, i.e. made with graphite oil it is blackish and yellow/green if made with normal car oil.