METAL. The two metals used in Heraldry are gold and silver, called or and argent. It is against the rules of Heraldry to place metal upon metal, or colour upon colour, unless for special reasons. Therefore, if the field be of any colour, the bearing must be of one of the metals, and on the contrary, if the field be of one of the metals, the bearing must be of some colour.
MILLRIND. The iron placed in the centre of a grindstone to protect the hole in the centre from the action of the axis; it is a charge frequently borne on escutcheons of persons connected with agriculture.
Ex. Argent, a millrind, gules.
MITRE. A sacerdotal ornament for the head, worn by Roman Catholic archbishops and bishops on solemn occasions. Certain English abbots formerly wore mitres, and they are frequently found as charges in the arms of abbeys and monasteries. The annexed is a representation of the mitre of the archbishops and bishops of the church of England, borne as a mark of distinction over the arms of the see, or over their paternal achievements, when impaled with the arms of their see. The prelates of the Protestant Church of England never wear mitres.
The Bishops of Durham were formerly princes of the Palatinate of Durham, and wore a ducal coronet surmounted by a mitre. They still retain the coronet and mitre as an heraldic distinction, borne over the arms of the bishopric.
MORION. A steel cap or helmet formerly worn by foot soldiers below the rank of gentlemen.