Black coral

Hawaiian black coral is a deep-water antipatharian found in significant concentrations on the walls and ceilings of Second Cathedral's deepest chambers, reaching sizes of 2 metres and ages exceeding 100 years in some colonies. Despite the name, the living tissue is golden-yellow or white; the jet-black skeletal axial material is what gives the genus its common name and historical value in jewellery. Hawaii is one of the world's few jurisdictions with a regulated black coral harvest; the colonies at Second Cathedral exist outside harvest zones and are among the more visually accessible deep-water colonies in the state.