Every piece of fine jewellery carries a signature — a set of stamped numbers discreetly placed on the inside of a ring, the clasp of a necklace, or the post of an earring. These markings aren’t decorative; they’re the industry’s way of recording a piece’s identity, purity, and provenance. Here’s what those numbers truly mean.
1. Metal Purity Marks (Hallmarks)
These are the most common numbers you’ll see. They tell you the precious metal content of the piece.
- 375 — 9ct gold (37.5% pure gold)
- 585 — 14ct gold (58.5% pure gold)
- 750 — 18ct gold (75% pure gold)
- 916 — 22ct gold (91.6% pure gold)
- 950 — Platinum (95% pure platinum)
- 925 — Sterling silver (92.5% pure silver)
These numbers are a promise: the metal is genuine, tested, and certified.
2. Maker’s Marks & Brand Signatures
Alongside purity numbers, you may see initials or tiny symbols. These are the jeweller’s signature — the equivalent of an artist signing a painting. They can identify the workshop, the designer, or the heritage of the piece.
For collectors, maker’s marks often add value and traceability.
3. Assay Office Marks (UK‑specific)
In the UK, hallmarked jewellery may also include a symbol representing the assay office that tested it:
- Anchor — Birmingham
- Leopard’s Head — London
- Rose — Sheffield
- Castle — Edinburgh
These symbols root the piece in a specific place and tradition.
4. Date Letters
Some jewellery carries a letter that corresponds to the year it was hallmarked. This is especially common in vintage and antique pieces, helping you trace the era of creation.
5. Additional Marks You Might See
- “CZ” — Cubic zirconia
- “DIA” — Diamond
- “PT” or “PLAT” — Platinum
- “Pall” — Palladium
- “GF” — Gold‑filled
- “GP” — Gold‑plated
These marks describe materials or treatments used in the piece.
Why These Marks Matter
Stamped numbers are more than technical details — they’re part of a jewellery piece’s story. They confirm authenticity, protect buyers, and preserve the craftsmanship lineage behind every design. For collectors, they’re a language that reveals exactly what they’re wearing.