in Natural History, is a substance which is distinguished from others by its ductility, malleability, tenacity, opacity, &c. for an account of which, see Chemistry.

in Heraldry. There are two metals used in heraldry, by way of colours, viz. gold and silver, in blazon called or and argent.

In the common painting of arms these metals are represented by white and yellow, which are the natural colours of those metals. In engraving, gold is expressed by dotting the coat, &c. all over; and silver, by leaving it quite blank.

It is a general rule in heraldry, never to place metal upon metal, or colour upon colour: so that if the field be of one of the metals, the bearing must be of some colour; and if the field be of any colour, the bearing must be one of the metals.