One of the natural treasures of Hawaii is the famed Black Coral, several species of which live in the euphotic ocean zone around the islands. In 1987, the coral was named the official Hawaii state gem.
There are some 230 known species of black coral, spread throughout the oceans of the world, mostly in the Indian and Pacific. Most of them live in very deep waters, at depths of between 300 and 3000 meters. However, around a dozen species make their home near land and sunlight, taking the form of large shrub-like or tree-like growths; you can see them first-hand if you take a diving trip at a Hawaii resort.
Like all other corals, black corals are colony organisms, with a large protein-based skeleton covered in a "coenosarc," a layer of tissue that connects the individual polyps to each other via a nervous and digestive system. The polyps, in turn, dot the surface of the coral with thousands of tiny mouths and tentacles turned out to catch prey and feed the colony.
Black corals are prized by jewelers because of their intense and unusual color. (Incidentally, in its natural habitat, black coral isn't black - the polyps are often brightly colored, but they're hiding a jet-black skeleton.) Unfortunately, they are extremely slow growers - the colony thickens by only between 4 and 35 micrometers per year. For this reason, many Black Coral species have become endangered, and the coral is subject to environmental protection laws that carry strict harvesting quotas.
For this reason, black coral jewelry can run you a pretty penny, depending on the species. While shallow-water Gorgonian black coral is relatively common and not terribly expensive, true deep-water Antipatharian coral, hauled from 300 feet below water and very strictly rationed, can cost hundreds of dollars for a 10-inch unprocessed branch. High-quality black coral gives an incomparable tone and luster, but is difficult to process, which drives up the price of jewelry even more.
If you can afford it, Antipatharian coral jewelry makes for a unique and precious gift for your Hawaii wedding!