Two real fossil ammonites polished halves have been matched for size and assembled into a spiral. You can see the internal structure of chambers in detail. These ammonites come from Madagascar. Mounted on a black plastic base.
Ammonites are extinct relatives of modern day nautiloids and squid. The largest known ammonite in the world would have been 8 1/2 feet (2.59 metres) across if it were complete.
1 1/4 inches (3.2 cm) wide, 3/8 inch (0.95 cm) deep and 11/16 inch (1.75 cm) tall.