Dating pierce watch case
Swiss gold and silver watch cases were not hallmarked in Switzerland until hallmarks for watch cases were introduced by law in 1880.Before that date gold cases were usually stamped with their carat fineness by the case maker, and silver was marked with its millesimal fineness, usually 800, or sometimes just "fine silver".
I don't make any attempt here to cover manufacturer's trade marks, of which there are thousands.The picture here shows a set of London import hallmarks for silver.NB: For clarity this picture does not include the sponsor's mark, but a set of British hallmarks is not complete and legal without a sponsor's mark.The new town marks shown below were used from 1 June 1907 on imported watch cases to distinguish them from watch cases made in Britain.If it is a silver watch case another clear indication is that the silver standard is given as .925 in an oval shield rather than by the traditional mark for sterling silver made in Britain of the lion passant, a walking lion with raised right forepaw.I will be publishing some corrections and additions to my NAWCC article that I will make available as a download here.
The following sections illustrate some characteristic marks to help you identify the type of marks you might find in a watch case and then link to a page that goes into more details about those marks.
Gold and silver watch cases submitted for hallmarking at a British assay office had first to be stamped with a identification mark registered at the assay office in question, and from this the identity of the person or company who submitted the item can be established.
Swiss watch cases were required to be assayed and hallmarked from 1880.
British practice changed in 1907 when it was ordered that all imported gold and silver watch cases be assayed and hallmarked in a British assay office.
From 1 June 1907 the assay offices were ordered to strike hallmarks on imported watch cases that were different from those struck on watch cases made in the UK.
In Britain gold or silver watch cases, wherever they were made, should always have been assayed and hallmarked in a British assay office before sale.