This cabochon is a section of the internal chamber of an Ammonite from the Middle Jurassic age. Iron Pyrite has replaced the ancient animal and shows lots of Pyrite crystals. This material comes from the Saratov region, Russia. It is set in sterling silver with an oxidized frame and open back behind the stone. Total length – 55.33 mm x 31.57 mm wide. Weight – 14.29 grams.