What Do Jewelry Stamps Mean and How Do I Verify Them Before Import?
What Do Jewelry Stamps Mean and How Do I Verify Them Before Import?
Problem: I once accepted a “925” chain lot that turned out 65 % copper—customers returned every piece.
Agitate: Those four tiny numbers erased two months’ profit and my Amazon rating.
Solve: I now read stamps like a metallurgist and double-check each batch with fast instruments.
Jewelry stamps reveal metal purity, origin, and legal compliance; decoding them and demanding matching lab reports stops plating fraud and six-figure fines.
Last week a Polish buyer slashed defect rates to 0.4 % after copying my stamp-audit checklist.
Which purity stamps matter most in bulk orders?
I grab a loupe before I open the packing list.
AU750 means 18 K gold (75 % pure), 925 signals sterling silver (92.5 %), and PT950 marks 95 % platinum—anything else needs an assay sheet.
Dive Deeper
H3 | Quick-Reference Purity Table
| Stamp | Metal & Standard | Precious-Metal % | Common Trade Name |
|---|---|---|---|
| AU585 | Gold | 58.5 % | 14 K gold |
| AU750 | Gold | 75 % | 18 K gold |
| 925 | Silver | 92.5 % | Sterling silver |
| SS316L | Stainless | — | Surgical steel |
| PT950 | Platinum | 95 % | Premium platinum |
Field tip: EU sellers often swap karat for decimal (e.g., 750). I ask suppliers to engrave both to avoid mix-ups in US customs.
H3 | Region-Specific Hallmarks
| Country | Mandatory Symbol | Assay Office Role |
|---|---|---|
| UK | Lion Passant (silver) | Tests & punches metal |
| France | Minerva Head | Adds national purity mark |
| USA | Purity + Maker ID | No state assay—buyer must test |
I always match the country icon to the invoice origin; mismatches scream trans-shipment risk.
How do I spot fake or tampered hallmarks on arrival?
Lasered fakes look crisp—but depth never lies.
Authentic stamps cut clean at uniform depth; forged overstamps show ragged edges, uneven depth, or sit on soft solder seams.
Dive Deeper
H3 | My Three-Minute Inspection Flow
- Visual Pass – 10× loupe check for doubled impressions.
- Depth Scan – Pocket profilometer; genuine laser ≈ 12 µm deep ±2 µm.
- XRF Shot – 3 points per piece; alloy must match stamp within ±0.3 %.
| Fraud Sign | Tool Needed | Reject Threshold |
|---|---|---|
| Overstamp blur | 60× microscope | Any ghost digits seen |
| Shallow laser | Depth gauge | <6 µm on premium line |
| Copper spike | XRF gun | >5 % Cu in AU750 lot |
I document every fail with a phone photo—suppliers refund faster when evidence is clear.
What legal penalties hit if stamps are wrong?
Customs officers love metal fraud cases; fines dwarf the cost of testing.
FTC can fine \$16 k–\$44 k per mislabeled item; EU and UK levy similar penalties plus seizure—lab reports are cheap insurance.
Dive Deeper
H3 | Key Rules by Market
| Region | Rule Set | Must Show | My Compliance Packet |
|---|---|---|---|
| USA | FTC Jewelry Guides | Karat OR fineness + maker | XRF sheet, maker registration |
| EU | Hallmark Convention | Assay office + CCM mark | EN 10204 3.1 cert, CCM photo |
| UK | Hallmarking Act | Metal mark + fineness + sponsor | Sheffield lab stamp log |
I attach digital copies of all three docs to each pallet. Border releases drop from days to hours.
Conclusion
Decode every stamp, test the alloy, archive the proof—small engravings guard big profit.