Hallmark
An official stamp on precious metal jewelry indicating metal purity, maker identity, and (in regulated markets) the assay office that verified it.
Last updated: July 6, 2026
Detailed Explanation
A hallmark certifies precious metal content through official stamps. The UK has one of the oldest compulsory systems (Hallmarking Act 1973): three marks required — sponsor's mark, fineness mark (e.g., 925, 750), and assay office mark (leopard's head = London, anchor = Birmingham). The US system is voluntary — manufacturers stamp quality marks (925, 14K, 18K) with registered trademarks, no independent assay legally required. China requires GB standard marks plus manufacturer code. The Vienna Convention (1972) established the Common Control Mark (CCM) recognized across 22 member countries.
Common Uses
All precious metal jewelry sold in regulated markets.
Advantages
Consumer protection, legal recourse for misrepresentation, provenance tracking.
Limitations
Voluntary in some markets (US), counterfeit hallmarks exist, not required for non-precious metals.