This is a war time Operculum sterling silver filigree necklace. This is one of the nicest I have ever seen with the drop being a heart. Soldiers gave these to their wives and girlfriends to keep a watchful safe eye out for them while deployed. The polished, bottom cut shell looks like an eyeball. The shells origin being the South Seas. There are no markings on the filigree but it does test sterling. 18 in. long and can wear shorter. The squares in the necklace are just shy of .75 in. and the heart drop is 1.75in. Rich in color and handmade detail and laced with war time history makes this piece a real keeper! Just LOOK AT THAT NECKLACE!