What Are the Marks for 18-Karat Gold?
The most common mark for gold-plated jewelry is GP or G.P. If you see a stamp such as "18K GP", this is an indication that the item is only plated with 18-karat gold, not made entirely of it. Other marks that denote gold plating are: RGP – rolled gold plate; HGE – heavy gold electroplate; HGP – heavy gold plate; GEP – gold electroplated
