Hallmark
An official mark stamped on precious metal jewelry to certify its purity, often with the maker and the testing office.
Common fineness numbers
| Mark | Meaning |
|---|---|
| 375 | 9 karat gold |
| 585 | 14 karat gold |
| 750 | 18 karat gold |
| 916 | 22 karat gold |
| 925 | Sterling silver |
| 950 | Platinum 950 or palladium 950, depending on the symbol |
Hallmarking around the world
Rules differ by country. The UK has assay offices that test and mark precious metal items above set weights. In India, BIS hallmarking applies to most gold jewelry sold by jewelers and includes a six character HUID code that identifies each piece. Other markets rely on maker's marks and fineness stamps without independent testing.
Hallmarks in CAD and renders
Some designers model a flat area for the hallmark inside the shank or on a tag, so the stamp has a clean place to land. You can show this in a close-up render if it is part of your brand story, but most product images leave it out, because the real stamp is applied after casting.
Do not add fineness marks to a render that the finished piece will not carry. Images should describe the real product. If you want to signal purity, put it in the listing text and use a metal colour that matches the karat you sell.