K stands for gold content, which is gold content.

RGP refers to alloy materials. When the gold content of the ring exceeds 5%, it is represented by the symbol GF, and when the gold content is less than 5%, it is represented by RGP.

GP is the abbreviation of English Gold Plate, commonly known as forging gold in business. This logo means that the products are mainly made of phosphorus-copper alloy in general metals, forged at high temperature and plated with a layer of gold. Therefore, 18KRGP refers to gold-plated or gold-plated jewelry with a coating of18kold.

reference data

Baidu encyclopedia-18krgp