A **metal** in heraldic tincture is one of the two pale tinctures, Or (gold/yellow) and Argent (silver/white). The rule of tincture forbids placing a metal upon a metal or a colour upon a colour, so flag designs derived from heraldry typically alternate metal with colour. The doctrine is not absolute: certain flags, notably the Vatican (gold and white) and the historic banner of Jerusalem (silver and gold), deliberately break the rule for symbolic effect.
**Example**: The white and yellow of the flag of Vatican City are both heraldic metals, an exception to the rule of tincture justified by the unique status of the Holy See.
**See also**: [color-heraldic](/glossary/color-heraldic/), [tincture](/glossary/tincture/), [or](/glossary/or/), [argent](/glossary/argent/)