**Fimbriation** is a narrow border of contrasting colour placed around a charge or along the edge of a stripe, used principally to separate two tinctures that would otherwise sit directly against one another. In strict heraldry, fimbriation prevents the violation of the rule of tincture, which forbids placing colour on colour or metal on metal; in vexillology it is also used for visual clarity at distance.
**Example**: The flag of South Africa uses fimbriation extensively: the green Y-shape is fimbriated in white against the upper red and lower blue panels, and in gold against the black triangle at the hoist.
**See also**: [tincture](/glossary/tincture/), [fimbriated](/glossary/fimbriated/), [metal-heraldic](/glossary/metal-heraldic/), [charge](/glossary/charge/)