This is a large Black Ammonite fossil sourced from Madagascar which has been been split down the middle and polished to reveal the intricate patterns and excellent fossilization. The unusual coloration of this piece is due to the mineral content of the rock in which it was fossilized.
Ammonites are an extinct group of marine invertebrate in the subclass Ammonoidea of the class Cephalopoda. The name "ammonite", from which the scientific term is derived, was inspired by the spiral shape of their fossilized shells, which somewhat resemble tightly coiled rams horns.
These molluscs are more closely related to living coleoids (i.e. octopus, squid and cuttlefish) than they are to shelled nautiloids such as the living Nautilus species.
The earliest Ammonites appear during the mid Devonian age roughly 350 million years ago, and the last species died out during the Cretaceous-Paleogene extinction event 66 million years ago.
Dimensions and weight are for the combined pair;