GP after the stamp stands for gold plated, "18K GP" means the item is electroplated with 18 karat gold. The imprint "18k HGE" on gold essentially means that the gold is costume jewelry with little or no value. Check out our 18k hge selection for the very best in unique or custom, handmade pieces from our rings shops. Check out our 18k hge ring selection for the very best in unique or custom, handmade pieces from our rings shops. The Meaning of 18K Gold Purity. Find many great new & used options and get the best deals for Ring 18K HGE AC HGE= Heavy Gold Elecroplated Ring - Size 7 at the best online prices at eBay!.