The nautilus is a marine creature that has tentacles and a prominent head, something that makes it very similar in form to other cephalopods. It has survived for millions of years, dating back to the dinosaur era, with relatively no changes. As a nocturnal marine creature, throughout its life, most of the time is spent in the greater depths of the oceans.

The major difference between the nautilus and the other marine creatures is the tentacles. The nautilus has a larger number of tentacles, up to ninety, they are arranged in two circles, they have no suckers, and they are undifferentiated and retractable. There are also some nautilus species that present some differences. Some are bigger in size, some have teeth, and others have gills.

The nautilus shell is also a major difference. They are the only cephalopods that have a bony structure externalized as a shell. It can also withdraw into its shell completely. A leathery hood is formed from two folded tentacles, thus closing the opening. The nautilus shell is calcareous and it can resist very high pressures, imploding only after it reaches a depth of 800m. It has two layers. The outer layer is of matte white color and the inner layer is white, but with iridescence. Iridescence is the optical phenomenon according to which the color of surfaces changes depending of the angle they are viewed from.

The nautilus shell is divided into chambers. The number of chambers depends on the maturity of the nautilus. The largest chamber, which is the last, is used as a living chamber. As it matures, its body is moved forward. The chamber in which he lived in before is sealed with a new septum. As the previous chamber is replaced, the number of chambers increases, going up to thirty.

The nautilus shell has a coloration that permits it to avoid observation. Viewed from the top, the shell is darker and decorated with irregular stripes. Viewed from underneath, the shell is completely white. This allows the nautilus to blend in with the darkness of the water when it is viewed from above and be hard to distinguish when you look at it from beneath. This is a very good and successful mode of camouflage that is also known under the name of countershading.

The shape of the nautilus shell is coiled. There are disputes on what pattern it follows. Some people say that it represents some of the best examples in nature of a logarithmical spiral, while others claim that it is follows the pattern of the golden spiral. The golden spiral is said to be obtained based on the golden ratio, which can be found in all living things.

The golden ratio, otherwise known as the golden mean, is mathematically named phi. This value has no arithmetic solution, with decimals continuing for eternity without ever repeating themselves. Plato named this unique number as ?the key for the universe physics?. The use of this value is spread to different areas like architecture, art and religion. It is a common belief that the use of the golden ratio in art and architecture makes the people like the works more. A very good example its use is the Guggenheim museum, which is also shaped in the form of a shell.

The shape of the shell can be interpreted as a symbol of expansion and renewal. For more information about this shape, what it represents or if you want to purchase jewelry shaped like a nautilus shell, be sure to visit ka-gold-jewelry.com.