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 to form dense limestone key beds. These limestone key beds are known as cephalopod beds, Orthoceras limestones or nautiloid limestones in the geological history.
These are slender, elongate shells range in length from a few inches to over six feet. Their middle body chamber is transversely constricted, which help them to swim and crawl on the ocean floor. Orthoceras could float by filling the chambers of their shells with air; they receive the thrust by squirting jets of seas water. When the die their shells accumulates on the ocean floor which then covered by sediments and subsequently over the ages transformed into stone.
Straight horn ‘Orthoceras’ are believed to be an excellent healing stone and are exquisite to carry on your body as jewelry. They are luck for the wearer and prosperous to have in his environment.
Beautiful ortho core nautiloids are yielded in the southern coast of Sweden, The Baltic island of Öland. For centuries, these straight horn ‘Orthoceras’ are used in jewelry and in various other articles, as these hard limestone fossil inclusions are durable for stairs, grave stones, and floors. Sporadically, the cavities of the fossil shells are colored in a different way which makes it very desirable. Colors are determined when the ground water minerals seep into the strata during diagenesis. Orthocerus crystals are of black and gray fossil, Brown and Green are most common colors. They fed upon small animals.