White Coral

According to CIBJO, Pleurocorallium konojoi is fished in the South China Sea and off Vietnam at depths of about 80–300 m, forming fan-shaped colonies 10–40 cm high. Kochi Prefecture in Japan, the centre of the country's coral fishery, also lists white coral among the precious corals taken off its coast. Precious corals live deeper than reef-building corals, which are not used as precious coral.

CIBJO notes that conclusive identification of a coral species is complex and usually needs advanced tests such as trace-element analysis and DNA fingerprinting. Bamboo coral, a common coral, has white calcite segments joined by dark organic (gorgonin) nodes and is commonly bleached. Coral can also be imitated by glass, plastics, dyed limestone, ceramics, bone and marble, or "reconstructed" from glued fragments; bleaching and other treatments should be disclosed.

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. Do not use ultrasonic or steam cleaners; clean it with a soft cloth and a brief rinse in warm, soapy water without soaking.

White coral was described scientifically by Kishinouye in 1903 as Corallium konojoi. Its species name honours Ebisuya Kōnojō, who devised a coral-collecting net in Tosa (now Kochi Prefecture); Kochi City dates the invention of such nets to the Tenpō era (1830–1843), when the Tosa domain still banned owning and selling coral.