Pink Coral

Precious coral lives deeper than reef-building corals and is collected below 50 m. Pleurocorallium elatius is fished off Japan and Taiwan at about 150–350 m and ranges from bright red, salmon and orange to flesh colour, usually with a lengthwise white core; Pleurocorallium secundum comes from Hawaiian and Midway waters at about 400–600 m. Kochi Prefecture, the centre of Japan's coral fishery, lists pink coral among the precious corals taken off its coast. The bamboo coral used for dyed imitations occurs almost worldwide, notably off Tasmania, New Zealand and the USA.

Under magnification, Corallium coral shows striations parallel to the branch and a concentric scalloped structure, which separate it from shell and plastic imitations; these features appear in both natural-colour and dyed coral. Dye is proved by colour concentrated in surface pits, cavities or fractures, but its absence does not prove natural colour, and not all dyed coral reacts to acetone; Raman spectroscopy showing carotene peaks near 1520 and 1123 cm−1 confirms natural colour. Bamboo coral consists of white calcite segments joined by dark organic (gorgonin) nodes. Other imitations include glass, plastics, dyed limestone, ceramics, bone, marble, and "reconstructed" coral glued from fragments and dyed. Some US dealers have reported that as much as 90–95% of new coral entering the market is colour-enhanced.

Coral is comparatively soft (Mohs 3 to 4), so keep it in its own cloth pouch away from harder gems. It is porous: avoid chlorinated pools, heat and chemicals, including cosmetics and perfumes, which can dull its polish and colour. Dyed coral can fade under prolonged sunlight. Do not use ultrasonic or steam cleaners; clean it with a soft cloth and a brief rinse in warm, soapy water without soaking.

Pink-to-red coral has a long history as an ornamental gem in jewellery, carvings and sculptures, and pieces are often carved to follow the natural form of the branch. In Japan, the Tosa domain record Nanroshi notes precious coral off Cape Muroto and Cape Ashizuri in 1813; the domain banned owning and selling coral, and rough-coral auctions in Kochi began only in the Meiji era.

Many cultures around the world have long believed that coral brings the wearer health, happiness, wisdom and success. In Japan, precious coral is still regarded as a charm for children's growth and for pregnant women, and as part of a bride's trousseau, according to Kochi Prefecture's product portal.

Ancient Romans thought coral quieted the waves of the ocean. During the Victorian era coral beads were worn to ward off evil spirits, as was traditionally believed. In the Hata district of Kochi, infants were traditionally given coral wrist beads, said to reveal a fever because coral clouds with sweat.