Recognized categories
Karat, fineness, mechanical layer, plating, electroplateSource-bounded mark lookup
Gold Jewelry Stamp Decoder
Enter a clearly legible mark such as 14K, 750, 14K GF or 12K RGP. The lookup recognizes only a documented set of karat, fineness and surface-layer terms; other marks are returned as unsupported rather than guessed.
Source-based reference
Source-basedNo live quote needed for this referenceUnknown marks
Returned unsupported; no guessNo metal assay
The decoder reads mark wording onlySpecification and intent
A stamp is a description to interpret, not a material test
The supported numeric fineness set follows published UK hallmarking references; karat and layer-mark examples follow U.S. FTC jewelry guidance. Marks need their jurisdiction, surrounding symbols and maker context; this tool does not assay an item or calculate recoverable metal.
Interactive tool
Check a jewelry mark
Enter the visible mark text. Supported examples include 14K, 750, 14K GF, 1/40 12K RGP and 12K GEP. The result describes the documented wording only.
Lookup statusUnsupported or not enteredEnter a mark to check; no interpretation is available yet.
The supported list is deliberately limited to cited examples. Spacing and case are normalized; other wording is not guessed.
Calculation method
How the result is calculated
The lookup normalizes case and spacing, then checks a finite allowlist of exact mark patterns drawn from the linked GOV.UK and FTC sources. It does not infer unstated thickness, base metal or gold mass.
A mark lookup does not verify who applied a mark or measure the item's actual metal content. Full UK hallmarks include additional marks; U.S. FTC guides describe qualifying wording, not a test of a particular item. Unknown and incomplete marks remain unresolved.
Evidence and references
Specification sources
Primary references where available
Information only, not investment advice. Theoretical metal value is not a dealer offer, retail price, jewelry appraisal, assay, or guaranteed sale price.