|
Coral:
Skeletons of simple marine polyps Calcium Carbonate CaCO3 AKA: Calcite |
|
System: Trigonal; microcrystalline. Much of their classification is based on microscopic details. Many forms may be identified by their gross anatomy, however, and with knowledge of the age of the deposit it is usually possible to place a specimen with its major group. Appearance: Red, pink, white, black and blue. Fracture; irregular, splintery, brittle. Streak; white. Physical properties: Hardness: (3 - 4); Specific gravity: (na); Cleavage: none. Translucent, opaque. Similar species: With conch pearl, cornelian, rhodonite. Imitations are made from glass, horn, rubber, bone and plastics. Occurrence: Deposits are found along the coasts of Western Mediterranean countries, the Red Sea, Bay of Biscay, Canary Islands, Malaysian Archipelago, the Midway Islands, Japan and Hawaii. The coral is found at depths of 1 - 1020 ft, and mainly harvested with weighted, wide-mesh nets dredged across a seabed. When harvested by divers, however, not as many corals are damaged. Miscellaneous: Corals may be colonial, that is consisting of many individuals or solitary. Shape is important and the growth form of colonial corals aids identification; they may be massive, forming clumps, or branching, or encrusting. An individual coral is considered a corallite and a complete group a corallum. Important internal featured are septa, that is radiating vertical divisions, tabulae, that is major horizontal divisions near the center of the corallite, and dissepiments, that is minor horizontal and slanting divisions near the walls. The axial structure may be a rod-like process or a diffuse vertical structure in the center of the coralline. Unworked coral is dull: when polished it has a vitreous luster. Conventional Wisdom: Coral is said to promote general physical and mental well-being and to be of particular assistance to those suffering from anaemia, bladder conditions, colic and whooping cough. In many parts of the world it is believed that coral can be used to ward off evil thoughts sent by ill-wishers. Belongs to the Astrological Sign of Pisces. |