Assay Office Symbols Guide

Hallmark Guide

Assay Office Symbols Guide

The Assay Office (town) mark shows where a piece was tested and hallmarked by an authorised UK Assay Office. This page is only about identifying the office mark — not purity tables, law, or sponsor marks.

UK assay offices London office mark How to read hallmarks
“Where” mark UK authorised offices Official verification links

Not covered on this page

  • Purity / fineness tables
  • UK legal exemptions and thresholds
  • Sponsor marks (maker’s marks)
Main Hallmark Guide London Assay Office process

What is an Assay Office (town) mark?

A UK hallmark typically includes a mark that indicates the authorised Assay Office that tested the item and applied the hallmark. That specific mark answers one simple question: “Which office hallmarked this piece?”

If you can identify the office mark, you can follow the correct official references for that office.

The four UK authorised Assay Offices

The UK has four assay offices that apply official hallmarks. Use the cards below for fast identification and official references.

London office mark (what to do if you see it)

If you spot the London office mark, the most reliable approach is to verify using official London Assay Office resources and compare the hallmark layout using our reading guide.

Majestic guides

How to Read a British Hallmark Step-by-step reading order and placement examples London Assay Office Certification How independent verification fits into our workflow

Official London references

LAO: What is a hallmark? Includes explanation of the Assay Office mark LAO: History of hallmarking Background and context from the Goldsmiths’ Company

FAQs

Is the assay office mark the same as the maker’s mark?
No. The assay office mark shows where the item was officially tested and hallmarked. The maker’s (sponsor) mark identifies who submitted the item.
What if I can’t identify the office mark?
Use angled light and zoom. Then use this page to narrow the office, and follow the official links for the closest visual match.
Where do I learn the full hallmark-reading method?
Use our “How to Read a British Hallmark” page. This page intentionally focuses only on identifying the office symbol.