Hallmarks are applied to all jewellery made in the United Kingdom that weighs over 7.78 grams (silver) and 1 gram (gold) and are applied to prove that your jewellery has been tested for fineness/purity. Some of my pieces have these hallmarks oversized and integrated into their design.
Shamrock and my initials RJH - Makers mark
.925 mark - Sterling silver purity
Lion Rampant - Traditional Scottish fineness
Edinburgh castle mark - Assay office
Letter mark - Year of assay