A laser hallmark is a mark of fineness and origin applied to a precious-metal article by a focused laser beam at an authorised assay office, in place of the older method of striking the marks with a steel punch. The four UK assay offices (London, Birmingham, Sheffield and Edinburgh), as well as several Continental and Asian offices, all now operate laser hallmarking as a standard service alongside punched marks, the choice between the two being driven by the construction of the article rather than by any difference in legal status.

Under UK law and the Hallmarking Act 1973, all the components of a UK hallmark, namely the sponsor's mark, the standard mark, the assay office mark and the date letter, may be applied either by punch or by laser, and the resulting mark carries identical legal effect. The reason laser hallmarking matters in practice is that many modern articles are simply too thin, too hollow or too delicate to take a punch without distortion. Hollow chain, lightweight earrings, thin-shank bands and bonded-construction items are routinely laser-marked because punch impact would crush or split the work.

Visually, a laser hallmark is shallower than a punch mark, generally cut to a depth of 30-50 microns, and the edges of each character are crisp rather than displaced. Under low magnification the surface inside each character shows the characteristic ablation texture of a pulsed fibre laser. The assay offices maintain registered laser font sets so that the marks remain consistent and recognisable across machines, and they typically retain digital records of every laser-marked article for traceability.

From a trade standpoint, the two consequences worth noting are that laser hallmarks are more vulnerable to disappearance under aggressive polishing or replating than equivalent punched marks, since they do not deform metal below the surface; and that, in some markets, dealers in second-hand and antique pieces will polish faintly laser-hallmarked items only with explicit care taken not to remove the marks, since their absence would force a re-assay before resale.