The skeleton of red coral is a branch complex, and each branch center has a horny skeleton axis, and the soft body surrounds the skeleton, and coral worms grow around the axis. The soft tissue of red coral consists of two layers of cells: endoderm and ectoderm. Coral secretes skeleton-red coral through ectoderm. After the coral dies, it still retains the appearance of dendritic red coral, and its interior is gradually replaced by calcium carbonate formed by the combination of free carbon dioxide and calcium ions in seawater. After thousands of years of incubation in the deep sea, it has become a delicate and touching coral organic gem.
Red coral is a symbol of wealth. In ancient times, only the royal family and nobles were qualified to wear and collect. Nowadays, with the diversification of jewelry collection industry, red coral is sought after by many collectors. How is the red color of red coral formed?
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As for how the red color of red coral is formed, it is generally said that coral grows in the sea and turns red when it meets iron ions. Especially, there are a lot of volcanic activities on the seabed in Taiwan Province Province and Japan. These undersea volcanoes provide volcanic ash, which contains some chemical elements. In the process of coral calcification, if iron ions are adsorbed, the coral will turn red.
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Coral absorbs magnesium and a little iron ion, so coral research will be pink or white; If the adsorbed element is mainly magnesium, it becomes white coral. This is the color theory of pigment ions, which is mainly caused by iron ions.
Another theory about the cause of coral coloring is metalloporphyrin coloring theory, which holds that coral is a marine coelenterate that catches food with tentacles. Coral absorbs elements containing trace heavy metals from food and combines with porphyrin in organic protein pigment to form metalloporphyrin. For example, chlorophyll is a metalloporphyrin composed of magnesium and porphyrin, and heme is a metalloporphyrin composed of iron and porphyrin. The content of these metalloporphyrins in various corals is different, which leads to different colors of corals.
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So coral will fade when heated, because porphyrin is decomposed when heated. For pearls with the same chemical composition as coral, many scholars have studied and analyzed them by Raman spectrometer, and concluded that the reason why pearls are colored is that the relative concentrations of carotenoids and metalloporphyrins in nacre affect the color quality of pearls.
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The third is the fine theory of organic matter. Before expounding this theory, we must first understand what is organic compound, which refers to carbon-containing compounds (except carbon monoxide, carbon dioxide, carbonic acid, carbonate, metal carbide and cyanide) or hydrocarbons and their derivatives.
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