rolled gold plated
RGP stands for rolled gold plated. An 18 RGP mark on jewelry means the jewelry is not a real 18k gold but only gold plated.
10k rgp means 10 karat gold rolled gold plate. In other words, it's gold PLATED.
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.
rgp 10 kt means its "rolled gold plated" of the 10 kt variety
It is Gold 18 ct
The term "18krgp" on jewelry indicates that the piece is made of 18-karat gold that has been gold-plated. The "18k" signifies that the gold content is 75% pure gold, while "rgp" stands for "rolled gold plate," meaning a layer of gold has been mechanically bonded to a base metal for durability. This marking assures buyers of the quality of gold used in the plating process.
RGP means Rolled Gold Plated and is a gold lining applied in the jewelry industry to watches, pens and the like. The amount of gold in a RGP product must constitute at a minimum 1/40th of the weight of the whole product. You can then refer to the 10kt gold price calculator link below to find out how much it is worth
No worries a lot of jewelry has markings like RL. Just the name of the business or person putting their stamp on it. Now something like rgp means rolled gold not much value. I have 2 14k RL sets of earrings and they 100% real.
"18 ct" means the ring is made of 18 carat white gold, indicating the purity of the gold. "RGP" stands for "Rolled Gold Plate," which means the ring is likely coated with a thin layer of gold. This indicates that the ring is not solid gold but rather a base metal plated with a layer of gold.
18k white gold
I suppose that you think to 18 kgp: the meaning is a metal "plated with 18 karat (75 %) gold".
Modified coins have no collector value, any value would be associated with the ring.