Also known as electroplating, the process of coating a non-gold metal with a layer of gold. The chemical process uses a plating solution to attract ions of gold to the surface of the piece. Measured in microns, where one micrometer = 0.001 milimeter, plating varies hugely in thickness. Micron gold plating deposits at least 1 micron of gold onto a base metal. Simple gold plating sees micron values of between 0.175 and 2.5 applied to a base metal. A layer of gold under 0.175 is known as flash-plating – it is extremely thin and will wear off quickly. See also gold vermeil.