Napoleonic period, C.1810-20. 2 5/8” diameter, circular, the two pieces joined with a cow horn ring. The top inset with a portrait of Nelson, on mica, covered with glass and sealed with a horn ring. Nelson in classic pose with his empty right sleeve pinned to his uniform. Nelson lost his right arm during the failed amphibious attack at Santa Cruz de Tenerife, Canary Islands, in 1797. Some degradation to the mica and overall wear.