A beautiful antique pair of old Sheffield silver plate wine coasters with grape vine motif and pierced edges. English hallmarks made in the 19th century. 
Old Sheffield Plate, or OSP for short, is the name given to silver plate made from a fusion process in the late 18th and early 19th century, before the invention of electroplating. 

For as long as there has been a demand for silver, there has been a demand for a more affordable substitute. This demand increased sharply with the rise of the merchant class in the eighteenth century and in the 1740s a cutler named Thomas Boulsover invented the first reliable and economic method of silver plating. An ingot of copper and a ingot of sterling silver were fused together and then rolled out into a sheet. This sheet (one side silver and one side copper) was then used to construct the desired item using the same techniques that were used with sterling silver. The vast majority of this fusion plate was made in Sheffield and hence the name Old Sheffield Plate.