coral

Coral has been used as a gemstone and carving material for millennia. Most goverments now only allow coral that has broken off naturally from its base to be used for these purposes, to protect the reefs and the other sea animals that live in and around them. It is most commonly white or off-white, but yellow, pink, red, and black are found naturally (and tourist traps often have coral dyed all sorts of colors).

Coral jewelry is delicate; it can be harmed by acids in sweat and change color, so settings that keep the gem away from your skin are preferable. (Polishing with a small amount of hydrogen peroxide is supposed to help restore the natural color.)

Corals usually feed at night on plankton and other microorganisms. They capture them with nematocysts, which are poison cells released from cells on their tentacles. They also have cilia around their mouths to aid in catching suspended food. Many tropical corals get energy from algae that live within their tissue and give the endodermal cells a yellow or brown color.

Coral polyps have many predators including parrotfishes, butterflyfishes, and sea stars.

Some of the things that coral can be made into are: limestone materials for road building, ornaments, and jewelry.

From: The Illustrated Book of Signs & Symbols, 1996

Cor"al (?), n. [Of. coral, F, corail, L. corallum, coralium, fr. Gr. kora`llion.]

1. Zool.

The hard parts or skeleton of various Anthozoa, and of a few Hydrozoa. Similar structures are also formed by some Bryozoa.

The large stony corals forming coral reefs belong to various genera of Madreporaria, and to the hydroid genus, Millepora. The red coral, used in jewelry, is the stony axis of the stem of a gorgonian (Corallium rubrum) found chiefly in the Mediterranean. The fan corals, plume corals, and sea feathers are species of Gorgoniacea, in which the axis is horny. Organ-pipe coral is formed by the genus Tubipora, an Alcyonarian, and black coral is in part the axis of species of the genus Antipathes. See Anthozoa, Madrepora.

2.

The ovaries of a cooked lobster; -- so called from their color.

3.

A piece of coral, usually fitted with small bells and other appurtenances, used by children as a plaything.

Brain coral, or Brain stone coral. See under Brain. -- Chain coral. See under Chain. -- Coral animal Zool., one of the polyps by which corals are formed. They are often very erroneously called coral insects. -- Coral fish. See in the Vocabulary. -- Coral reefs Phys. Geog., reefs, often of great extent, made up chiefly of fragments of corals, coral sands, and the solid limestone resulting from their consolidation. They are classed as fringing reefs, when they border the land; barrier reefs, when separated from the shore by a broad belt of water; atolls, when they constitute separate islands, usually inclosing a lagoon. See Atoll. -- Coral root Bot., a genus (Corallorhiza) of orchideous plants, of a yellowish or brownish red color, parasitic on roots of other plants, and having curious jointed or knotted roots not unlike some kinds of coral. See Illust. under Coralloid. -- Coral snake. Zo (a) A small, venomous, Brazilian snake (Elaps corallinus), coral-red, with black bands. (b) A small, harmless, South American snake (Tortrix scytale). -- Coral tree Bot., a tropical, leguminous plant, of several species, with showy, scarlet blossoms and coral-red seeds. The best known is Erythrina Corallodendron. -- Coral wood, a hard, red cabinet wood. McElrath.

© Webster 1913.