Red coral is called "angel's skin".
White coral-mainly used as ornamental stone.
Black coral-rare
Blue coral-rare
Red coral belongs to eight-shot coral.
1. Material composition: It consists of inorganic and organic parts.
Inorganic substances: high magnesium calcite, a little apatite, CaCO3, MgCO3, a little H2O, FeO, Ca4(PO4)5(OH)2.
Organic matter: mainly keratin.
2. Structural features: wavy parallel fiber structure.
Along the longitudinal direction of coral branches, there are different shades of color or transparency, forming a continuous wavy parallel fiber structure. The cross section is concentric, like tree rings. There are many round pits on the branches, which are places where corals nest.
3. Physical and chemical properties
The colors are crimson, fiery red and pink. Dendritic. The bones are dense and tough. Hm=3.5-4, opaque-translucent. The raw materials are dark in color, waxy in luster after polishing, and resistant to acid, organic solvents and volatile gases.
Red coral symbolizes calmness, wisdom, peace and good luck. ? In modern times, red coral is the birthday stone in March and the 35th wedding anniversary. ? Red coral is the court decoration of past dynasties. Coral trees, bonsai, concubines and princes are crowned. ? Red coral and pearls are one of the seven treasures of Buddhism. ? Red coral was recorded in China at the beginning of AD. ? "When pearls meet jade, it is difficult to find wood among corals" (Cao Zhi, 192 ~ 232)