Hallmarks · By country
American hallmarks
There is no assay office and never has been. American marks are claims made by the maker and enforced after the fact, not guarantees tested in advance.
- Marking since
- 1906
- Gives a year
- No
How the system works
The National Gold and Silver Stamping Act of 1906 requires that a stamped fineness be accurate within a legal tolerance and, from 1961, that a registered trademark accompany any quality mark. Enforcement is by prosecution rather than by testing before sale.
The standards
| Figure or mark | Fineness and use |
|---|---|
| STERLING | 925 silver. |
| COIN | About 900 silver, mostly pre-1870. |
| 10K | 417 gold, the American legal minimum. |
| 14K | 585 gold, the American default. |
| 18K | 750 gold. |
| PLAT or IRIDPLAT | Platinum, often with ten per cent iridium. Characteristic of 1900 to 1950. |
Dating a american piece
There is no date mark. American pieces are dated by maker's mark, by patent number, by the presence of a copyright symbol, and by construction.
Where the marks will not give you a year, date the piece from its construction instead: the catch, the metal, the setting and the cut of the stones. That method is set out in how to date antique jewelry.
Where people go wrong
- A copyright symbol beside a maker's mark means 1955 or later. It became common on costume jewelry after a run of design theft lawsuits in the mid 1950s.
- COIN or COIN SILVER means about 900 fineness and generally predates the adoption of sterling in the 1860s.
- A patent number can usually be looked up and dated precisely, which makes it the most exact tool available on unmarked American work.
- STERLING spelled out in full is typically American or British. A bare 925 with no trademark on an American-styled piece is more likely to be a modern import.
Other countries
United Kingdom · Ireland · France · Germany · Denmark · Sweden · Norway · Finland · Netherlands · Russia and the Soviet Union · Austria and Hungary · Italy · Switzerland · Mexico · Portugal · Spain · India · China and Hong Kong · Japan · Turkey and the Ottoman Empire · International marks