4.75" Cut/Polished Ammonite Fossil - Unusual Black Color

Most ammonites preserve in shades of brown or yellow, so this unique orange and black coloration is quite unusual. These have been collected from a different location and the difference in coloration would be due to changes to the local geochemistry after the ammonite was fossilized. The colors seen here were probably caused by the addition of manganese. You'll notice some of the attached matrix on the back side is a deep orange color instead of the typical grey from the other localities, further hinting at these changes.

Ammonites were predatory cephalopod mollusks that resembled squids with spiral shells. They are more closely related to living octopuses, though their shells resemble that of nautilus species. True ammonites appeared in the fossil record about 240 million years ago during the Triassic Period. The last lineages disappeared 65 million years ago at the end of the Cretaceous.