What does 18K GP mean on jewelry?
Short answer
Gold plated (GP, GEP, HGE: electroplate): a layer microns thick over base metal. The karat figure describes the layer, not the piece.
The melt value of a plated piece is practically nil.
The stamp in detail
| Item | What the tables say |
|---|---|
| Stamp | 18K GP |
| Class | Plated, filled or rolled coating |
| Karat figure | 18 karat describes the coating, not the piece |
Is there any melt value?
The melt value of a plated piece is practically nil.
If you still want to try numbers, the calculator does the sum for a stamped fineness. It will not compute one for a plated or filled stamp.
What 18K GP can be mistaken for
Pieces that look like gold and are not:
- plated and gold filled
- pinchbeck and gilt brass
- silver gilt (vermeil)
What a stamp cannot settle: The metal. Colour is not a fineness, and a mark can be forged.
What settles it:
- Magnet: if it sticks, it is not solid gold (not sticking proves nothing).
- Jeweller: touchstone and acids, or X-ray fluorescence, in two minutes.
Related stamps
Also in this group: GF, 1/20 12K GF, RGP, GP, HGE, GEP, VERMEIL, EPNS.
Frequently asked
What does 18K GP mean on jewelry?
Gold plated (GP, GEP, HGE: electroplate): a layer microns thick over base metal. The karat figure describes the layer, not the piece.
Is a piece stamped 18K GP worth melting?
The melt value of a plated piece is practically nil.
Sources
All sources are listed with the method on the sources page.