I have an unmarked item that looks just like a wine coaster, but is approximately 9 inches diameter and 3 and 3/4 inches tall. The base is a polished ogee, about 1/2 inch high. This portion shows a slightly open seam, each side of which is nailed to the wood base with what appear to be small rosehead nails. There is another nail on the other side which appears more modern. There is no evidence of a seam at this point. Above the base in a reverse ogee is a pierced band of stylized grape or ivy leaves in double circle and heart-shaped "vines" the leaves and the "vines" are engraved. This band of decoration is also seamed at the same place as the base. Above the reticulated band, is a flat crown with six slightly pointed arches like a crown. The top edge is gadrooned on the outsid edge only. The gadrooned decoration appears to be joined at each low point of each arch. One of these seams appears to have been repaired. The wood base lookks like dry, originally wax- finished hand- planed mahogany. Age shrinkage, possibly aided by dampness, has cracked the wood with the grain. Only the nails and the baise backing hold the wood in place.
I thought it was probably electroplate, but after taking off tarnish I think it at least Sheffield. What appeared to be base metal inside the rim, will come off with sufficient rubbing with cleaner or with my fingernail. I can't find evidence of copper or brass. The item isn't attracted by a magnet.
What is it and why isn't it marked? Is it possible it's marked where the wood covers the mark, and if so should I remove the nails to see? i have photos I can email.