Ammonites are a form of Ammonoid. They represent a large group of more than 10,000 species of extinct cephalopods. A faceted Oregon Sunstone, approximately 10 mm in size is set next to the Ammonite. A bail to accomodate a chain is mounted in the back. The back is open behind the stones. Total length – 37 mm x 30 mm wide. Weight – 15.46 grams.