You are at : Site Map > Education and Guidance > Hallmarking Hallmarking This is the process by which a precious metal’s purity is independently guaranteed. Without a hallmark it is illegal to sell a piece of jewellery made of precious metal. Hallmarking involves testing items made of precious metal and marking them to indicate that they are of a minimum standard of purity.   Hallmarking takes place in the UK at Assay offices in London, Birmingham, Sheffield and Edinburgh. Why Hallmark? Precious metals are not used in their pure state for jewellery, most often because of their softness. Other metals (alloys) are added to them to make them less hard and less expensive – and in the case of gold to give differing colours. It is impossible to observe (using your eyes) how much of the less expensive alloying material has been used, therefore fraud is easy. The customer loses out as they receive less than what they paid for. The only guarantee against sub-standard metal is an independent system of testing, the ASSAY and HALLMARKING carried out in secure conditions and to the highest standards. What does a Hallmark consist of? A Sponsor’s Mark The initials of the person or the firm responsible for sending the articles to an Assay Office. The mark must be registered at the Assay Office of their choice.   A Standard Mark This is the mark that shows the metal being used and the guarantee of purity. The shape of the mark indicates which metal the item is made from.   Metal Shape of Mark silver Oval gold Oblong with cut corners platinum Five sided ‘house end’ Within the shape a number is shown which represents the purity of the metal. It is described as the fineness and is shown in parts per thousand. Metal Fineness shown within Mark Silver 800, 925(Sterling), 958 (Britannia) and 999 Gold 375 (9ct), 585 (14ct), 750 (18ct), 916 (22ct), 990 and 999 Platinum 850, 900, 950 and 999   The Town Mark This indicates where the item was assayed. Each Assay Office has a different symbol. Assay Office Symbol Birmingham Anchor Edinburgh Castle London Leopard’s head Sheffield Rose The Hallmarking Process Items are sent to the Assay Office where registered. Items are clearly labelled and bagged separated. Once received by the Assay Office the item is weighed and tested according to the metal. Once the test has been passed they are then hallmarked by having the 3 various marks applied by hand, by press or by laser. After these items are checked they are ready to be returned to the sponsor. All Ralph Blacklock jewellery is hallmarked.