Orthoceras are fossils found in the High Atlas Mountains of Morocco and are 400 million years old. The distinctive bullet-like shell was once divided into gas-filled chambers which kept the creature buoyant in the water. These are now fossilised in black limestone and often shaped and polished into decorative pieces such as these small oval shaped stones. These are genuine fossils and each decorative nautiloid is a unique fossil. These orthoceras nautiloids measure approximately 4.5cm long and 2cm wide. We always choose the best quality stones from reputable importers we have met and trust but can’t photograph every piece as they come in and change them as they sell so we try to keep an image on the site that is a good example of that item. If you have any questions regarding a natural stone item please contact us and we would be happy to help. © Please do not copy text. Avena product description – Orthoceras Nautiloid Small.