Tourism: Diamond Head Oahu

Diamond Head Oahu: Diamond Head is the name of a volcanic tuff cone on the Hawaiian island of Oʻahu and known to Hawaiians as Lēʻahi, most likely from lae 'browridge, promontory' plus ʻahi 'tuna' because the shape of the ridgeline resembles the shape of a tuna's dorsal fin. Its English name was given by British sailors in the 19th century, who mistook calcite crystals embedded in the rock for diamonds. Diamond Head is part of the complex of cones, vents, and their associated eruption flows that are collectively known to geologists as the Honolulu Volcanic Series, eruptions from the Koʻolau Volcano that took place long after the volcano formed and had gone dormant.