What are metal clays?

Some articles on metal clays:

Base Metal Clays
... Base metal clays, such as bronze, copper, and steel metal clays are best fired in the absence of oxygen to eliminate the oxidation of copper by atmospheric oxygen ...

Famous quotes containing the word metal:

    We are supposed to be the children of Seth; but Seth is too much of an effete nonentity to deserve ancestral regard. No, we are the sons of Cain, and with violence can be associated the attacks on sound, stone, wood and metal that produced civilisation.
    Anthony Burgess (b. 1917)