Hallmarks are the symbols, numbers and letters stamped onto a gold object such as a ring to prove its quality and provenance by an assay office. Typically on a gold ring you might see:
The Sponsor’s Mark – usually a series of initials to determine who it was that went the ring for assaying (usually the producer).
The Standard Mark – the number that determines the quality of the gold, essentially a purity rating out of 1,000.
375 = 9 carat gold
585 = 14 carat gold
750 = 18 carat gold
916 = 22 carat gold
999 = 24 carat or ‘pure’ gold
The Assay Office Mark – this is the mark of the office that ‘assayed’ the metal. The UK has four assay offices.
Date Mark: Like a car’s number plate this is done by letters. The letter for 2018 is ‘T’.
Traditional metal mark: This denotes which metal it is.
Crown = gold
Orb = platinum
Greek Head = palladium
Britannia = Britannia silver
Lion = sterling silver