Hallmark Guide
What Is a Hallmark?
A hallmark is an official mark applied by an authorised UK Assay Office, confirming the purity of a precious-metal item. It provides independent verification of gold, silver, platinum or palladium content.
How to Read a Hallmark
A complete UK hallmark typically includes a sponsor mark, a fineness mark (such as 585 for 14K gold) and an assay office mark. For a full step-by-step explanation and placement examples, see the dedicated guide.
Read the full hallmark breakdownGold Fineness Reference Table
| Karat | Fineness | Gold Content |
|---|---|---|
| 9K | 375 | 37.5% gold |
| 10K | 417 | 41.7% gold |
| 14K | 585 | 58.5% gold |
| 18K | 750 | 75% gold |
| 22K | 916 | 91.6% gold |
| 24K | 999 | 99.9% gold |
Majestic Jewellery specialises in 14K gold (585), with 9ct and 18ct available to order.
Majestic Jewellery Sponsor Mark
Our registered sponsor mark appears as CMJ. This identifies the responsible company that submitted the piece for independent hallmarking.
Independent Verification
Eligible pieces are submitted to the London Assay Office for independent testing and official UK hallmarking, so metal purity is externally verified rather than self-declared.
Learn about the London Assay Office process