Natural 23.45cts orthoceras black cabochon 42.5x12 mm pear loose gemstone s11341

Orthoceras

Along conical shape Orthoceras ‘cephalopod’ is the fossilized remains of an extinct marine animal. Orthocears are the remains of extinct marine animals, therefore, known as the fossil stone and is around 400 million years old. The ancestor to the squid, over 500 to 190 million years ago, they are marked with a date to the lower Ordovician to Triassic ages. Orthoceras fossils ("straight horn") are common and have a global distribution, a genus of extinct nautiloid cephalopod they occur in any marine rock; in particular they occur in limestone. These conspicuous ortho core cephalopods ‘Orthoceras’ are persistent enough ... Click to Continue »