The Goldsmiths’ Company Assay Office has announced the opening of its first hallmarking facility located within a retail jeweller.

Opened at the beginning of November 2015, the in-house assay office is located within a purpose built facility at Graff’s London workshop and has its own dedicated member of the Goldsmiths’ Company Assay Office.

Graff is always involved in every stage of the jewellery making process – from the sourcing of each rough stone, right through to the cutting, polishing and final setting of each exquisite jewel. The addition of this unique facility is a continuation of Graff’s dedication to pushing the boundaries of innovation and excellence.


The in-house assay office enables each diamond or gemstone jewel to receive the highest quality hallmarking. Convenience also plays a major role as the supply chain is shortened heightening the efficiency levels of production. Lastly, dedicated staff and specialist equipment ensure excellence in service whilst maintaining discretion and privacy.

The UK compulsory hallmark comprises three component marks: the sponsor’s mark indicates who sent the article in for hallmarking. The millesimal fineness mark denotes the purity of the precious metal. The assay office town mark specifies where the article was hallmarked.

Each sponsor’s mark is unique, and Graff naturally has its own ‘G’ and ‘D’ representing Graff Diamonds.

Graff will have its jewellery pieces marked with these three marks – Graff’s sponsor’s mark, the metal fineness mark and the town mark.  In addition Graff will also have the Common Control mark.  The combination of these four hallmarks is called a Convention Mark.  The UK has been a signatory to the International Convention on Hallmarks since 1972.  This means that the Goldsmiths’ Company Assay Office can strike the Convention Hallmark which will then be recognised by all member countries in the International Convention (19 European countries). So, this mark eases and ensures safeguards for the cross border trade of Graff’s jewellery.

“Opening our first hallmarking facility within the manufacturing premises of a UK retail organisation is a very special occasion,” says Dr Robert Organ, deputy warden at the Goldsmiths’ Company Assay Office. “We are thrilled to be partnering with Graff, a British company at the pinnacle of the luxury jewellery industry. The sub-office is equipped with state-of-the art assaying and laser hallmarking systems to best suit and align with their outstanding jewellery design and manufacturing processes.”

Raymond Graff, director of production at Graff, comments: “We have one of the most prestigious fine jewellery workshops in Europe, through passion we create perfection. Having access to an on-site assay office will improve our processes and in addition to our vertical integration provide us with the flexibility and accuracy we need to continue pushing boundaries and growing our business.”

Graff continues: “Over the years we have handled the world’s most fabulous and treasured gemstones, it has been said that more important gem quality diamonds have passed through the House than any other. We are delighted to be the first jeweller to have an on-site assay office and to partner with the Goldsmiths’ Company to combine our expertise and exemplary mark of quality.”