The coral is a colonial animal, a small polyp (a few millimeters in diameter) that form in rigid structures due to its ability to fix the calcium dissolved in the sea on their tissues. These calcareous skeletons are colonies that may be branched, compact or even flexible. Although the polyps die, these structures are conserved to be colonized by new generations forming reefs.

Coral reefs are food bank for many species that use these to avoid predators. Because of its size some reaching to the surface and reach lengths impressive as the Great Barrier Reef (in Australia) over 2,200 kilometers long.

The ideal conditions for the development of a coral reef are: water temperature between 20 and 28 ° C and crystal clear water that promotes the passage of light.
There are many types of coral, but only we will talk about those interested in jewelry or personal adornment.

To have a basic knowledge of coral like gemological material, we attach the information in the source cited, and we have selected it for their quality and content. Indeed, we recommend you that report before buying a piece because the reef is a protected species, with serious danger of extinction, and sometimes, their extraction is prohibited.

The CORAL by http://www.dejoyas.com

Coral is one of the materials used in jewelry and gem of organic origin, in this case of animal and marine origin.
The coral is actually the calcareous external skeleton or exoskeleton of a sea animal, the coral polyps.

The coral gem is a sedimentary organic matter. It is like a stone and it have the shape the skeletons of tiny soft bodied animals (polyps). They live in colonies and build branched forms to reproduce and create mass we know as coral reefs.

This gem of nature is not very hard, some varieties are very fragile, they are porous and 50% of its volume is empty.
Coral reefs are often located in shallow coastal waters, at 100 meters deep, which can reach about 300 depending on the species.

How is the coral?

Observed superficially, externally or in its structure, the natural coral is more like a vegetable or a mineral than an animal.
Polyps that manufactured these, precipitate and deposite calcium carbonate (CaCO3), which forms an external skeleton or exoskeleton limestone, which is the vital structure in which they live. In that structure they feed and get a hardness similar to that of a limestone, which causes some confusion with a mineral.

There are many species of coral. It is estimated that in the Pacific and Atlantic live some 100 genera and 800 species of reef-building corals.

The coral growth is extremely slow and uninterrupted, between one and one and a half inches a year. In thousands of years is built a reef coral.
The coral structure is radial, forming circles which grow from the center of each branch. This is shown in a section of it. Most modern reefs began to form about 15,000 years ago.

The coral needs to develop certain conditions: temperatures above 21-22 ° C and well-lit funds because they need light and high salinity.
Corals grow where waves and currents carry the plankton that is a feed for the polyps. They grow where water movement removes sediment from the surface of corals.