Vintage Deco Marcasite Sterling Blue Stone Necklace. This circa 1930 necklace is crafted and hallmarked of sterling silver. The diamond shaped pendant measures one and three quarters by one and one eighth of an inch. It is designed with open filigree work accented by marcasites and set with a vibrant blue stone. The pendant suspends from this 17'' chain. This estate find is in very nice condition with age appropriate wear.