What kind of material was used?

by Nicholas Lloyd
(Vicenza, Italy)

I recently purchased a cameo on ebay from a reputable dealer. I believe it's pink conch but it's hard to tell. The back is curved and the frame uneven so I believe it isn't plastic or molded. The carving seems to be well done and intricate. Here is the listing that has photos of it:

http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=160724109774

I was wondering if you might be able to help me both date the piece and figure out what the material is. I live in Italy so I was thinking of taking it to Torre del Greco to have it appraised. Any information you could give me would me much appreciated!