Coral is the oldest marine life on earth, which appeared nearly 500 million years ago. Many people think that coral is a plant, but in fact, from a biological point of view, coral is an animal, which is made up of countless tiny corals.

Coral is a coelenterate. It is very small, often only a few millimeters, exquisite, colorful and very delicate. It can only live in water with a temperature of 22-28 degrees Celsius all the year round, and the water quality must be clean, transparent and sunny. Don't be exposed to water for a long time at low tide. Only by meeting these harsh conditions can corals flourish and build coral reefs.

Coral is shaped like a flower, the top of which is composed of coils of tentacles, like petals, and the cylinder is like the ovary of a flower. Coral absorbs calcium carbonate dissolved in seawater to make its own bones. The white coral we usually see is actually the bones left after the death of the coral. The real living coral is the tender "little flower" that opens on it.

There are many kinds of corals, such as red coral, black coral, blue coral, Japanese coral and Mediterranean coral. Different kinds of corals have little difference in quality, so the color and size of their colors become the standard of price verification and the basis for customers to buy.

Due to the differences in history, civilization, customs and culture of different countries, their evaluation of coral value will be different. Coral, as a natural gem, has great ornamental value and collection value.

Extended data

Classification and function of coral reef coast;

Generally speaking, coral reef coasts are mainly divided into three categories, namely shore reefs, atolls and barrier reefs. Shore reef is a coral reef close to the coast. Embedded in the coastal area like lace, the width is generally between 100 m and 1000 m. There are reefs on Taiwan Province Island and Hainan Island in China.

Atoll is a coral island exposed to the sea, shaped like a wreath, with a lagoon with water in the middle, with a water depth of about 40 meters; Among the South China Sea Islands in China, many islands and reefs belong to this category. Barrier reefs are generally on the sea surface at a certain distance from the shore, and are composed of dike-like coral reefs. It is parallel to the coast like a natural long dike. The most famous barrier reef in the world is the Great Barrier Reef off the northeast coast of Australia.

Coral reef coast can effectively block the erosion of waves and storm surges, and is a natural breakwater; The special water environment formed by coral reefs is suitable for fish and shrimp to inhabit, which is conducive to attracting fish and shrimp to settle here and multiply fishery resources; Graceful corals and strange reefs are beautiful natural landscapes, which can be used as rich tourism resources if properly developed. Australia's Great Barrier Reef has been opened as an underwater park, which is a rare tourist attraction in the world.

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