Hallmarking & Materials
Last updated: 21 May 2026
What Hallmarking Means
A UK hallmark is the official mark applied to qualifying precious metal jewellery by an authorised Assay Office. It confirms that the metal has been independently tested and certifies its purity.
Hallmarking protects customers. It is one of the oldest forms of consumer protection in the UK, ensuring that a piece described as silver, gold, platinum or palladium genuinely meets the stated fineness.
THE LAB Jewellers is registered with the London Assay Office and uses approved laser-marking processes for qualifying pieces.
UK Hallmarking Thresholds
Under UK hallmarking law, precious metal articles above the following weights must be hallmarked before they can be described as that metal:
- Silver: above 7.78g
- Gold: above 1g
- Platinum: above 0.5g
- Palladium: above 1g
Where UK hallmarking law requires it, qualifying THE LAB Jewellers pieces are submitted for hallmarking before dispatch.
A product will only be described as hallmarked where this is accurate and supported by assay evidence.
Dealer’s Notice
The Hallmarking Act 1973 requires registered dealers to display the official Dealer’s Notice issued by an Assay Office, explaining the approved hallmarks customers may encounter on UK jewellery.
The official Dealer’s Notice B issued by the London Assay Office is displayed in our showroom and is available on request. We will add the official notice image to this page as soon as it has been formally supplied for display.
Metals We Use
THE LAB Jewellers works in the following solid precious metals:
- 925 Sterling Silver — 92.5% pure silver, alloyed for durability. A widely recognised standard for fine jewellery.
- 10kt Gold — 41.7% pure gold. A harder, more durable alloy that holds shape and finish well over time. Available in white, yellow and rose.
- 18kt Gold — 75% pure gold. Higher purity, richer colour, softer feel. Available in white, yellow and rose.
All metals we use are solid throughout the piece, not plated. White gold pieces are finished with rhodium, which may require periodic replating over time as part of normal care.
Lab-Grown Diamonds
Every diamond we set is lab-grown.
Lab-grown diamonds are chemically, physically and optically identical to mined diamonds. They are graded using the same 4Cs — carat, colour, clarity and cut — and are real diamonds in every measurable way. The only difference is origin: ours are grown in controlled laboratory conditions rather than extracted from the earth.
This allows us to offer larger stones, higher quality grades and cleaner provenance at a more accessible price point than equivalent mined-diamond jewellery.
Certification
Lab-grown diamond certification — including IGI and GIA certification — is available on request for individual pieces where agreed in writing.
Certification confirms the carat, colour, clarity and cut of a stone and provides a formal grading report from an independent laboratory.
A piece will only be described as certified where the relevant certificate exists and matches the supplied stone. Certification may increase the final price and extend the lead time.
Product-Specific Evidence
Specific hallmark details, certification reports and material evidence for individual pieces are available on request. Email info@thelabjewellers.com if you would like documentation for a piece you have purchased or are considering.