London Assay Office: The Hallmarking Process - Testing

Before an item can be hallmarked its purity must be ascertained. This is called assaying. Assaying is an ancient process and has been used for metal authentication for over 2,500 years. The Goldsmiths’ Company Assay Office has been assaying traditionally for nearly 700 years. Today most assaying is done using an X-ray fluorescent (XRF) spectrometer. Watch this video to see how it works.

The Hallmarking Process - Testing

The Goldsmiths’ Company Assay Office is where hallmarking began, and we have been testing and hallmarking precious metals for over 700 years. At the Goldsmiths' Company Assay Office we provide both traditional handmarking and the latest laser marking techniques across three key London locations with a choice of three priority services including one hour, same day and early hall. We process 3 million articles a year, in 100,000 packets, and are proud to apply the leopard's head townmark of London to each and every one.