What is 18 k RGP?

Jewelry engraved with RGP, which stands for Rolled Gold Plating, or plaqué d'or laminé, (proper designation: 1/30 14 kt.), contains approximately 100 times the average amount of gold utilized in gold plating (which is either sprayed or dipped). Rolled Gold Plating involves the lamination of a thin sheet of gold leaf with a lesser metal (usually brass), fused by heating under pressure.