Is Diamond Head A Volcano?

An aerial view of Diamond Head, Hawaii.
An aerial view of Diamond Head, Hawaii.

Diamond Head is a volcanic feature situated on the Oahu Island in Hawaii. A volcanic tuff cone, Diamond Head was formed after debris released during a violent eruption at least 0.4 million years ago, cemented together to form volcanic rock known as a tuff. The volcanic cone is the most prominent feature on the island, with its summit towering 762 feet in elevation and 596 feet in prominence. Part of the volcanic cone has important government structures including antennae and is, therefore, closed from the public. Nonetheless, Diamond Head is still a top destination in Hawaii for hikers.

Formation Of The Diamond Head

The Honolulu Volcanic Series is a collective name for volcanic eruptions which resulted in the formation of numerous volcanic features found throughout the Hawaii Islands which include the Diamond Head volcanic tuff cone. Other volcanic features associated with the Honolulu Volcanic Series include Koko Head, Punchbowl Crater, and Manana Island among others. Geologists estimate that the volcanic cone was formed between 0.5 and 0.4 million years ago after a violent eruption spewed tons of ash and other debris into the atmosphere. The debris would later solidify into a volcanic rock known as a tuff, forming a volcanic crater.


The native name for the volcanic cone is ‘Le’ahi,’ a combination of the words ‘Lae’ (browridge) and ‘Ahi’ (tuna). The name is believed to stem from the cone’s resemblance to the dorsal fin of a tuna. The British sailors who visited the island in the 19th Century gave the volcanic cone its name ‘Diamond Head.’ The origin of the name was after the sailors thought the calcite crystals on the beach were diamonds.

Tourism To The Diamond Head

Diamond Head was designated as a US National Natural Landmark in 1968. A distinctive physical feature towering the island of O’ahu, the Diamond Head volcanic cone is a popular tourist site in Hawaii, drawing thousands of visitors each year. Among the most popular activities on the volcano is hiking. Hiking trails made up of a series of steps guide hikers up the slopes of the Diamond Head. Nested on the summit of the volcanic cone is the Diamond Head Observation Station where one can get extensive views of the entire island of O’ahu, including the city of Waikiki. One can even view the University of Hawaii, the Pali Mountains, and Hanauma Bay while on the observation station. Ascents are typically before sunrise and gives one scenic view of the picturesque Hawaiian tropical sunrise.

Notable Features

On the slopes of the volcanic cone lies an old lighthouse known as the Diamond Head Lighthouse. Built in 1917, the lighthouse was in 1980 designated under the National Register of Historic Places. With a focal height of 147 feet, the Diamond Head Lighthouse has a range of over 14 nautical miles. The existing lighthouse is the second one on Diamond Head, with the original one having been built in 1898. Another historic feature found on the volcanic cone is Fort Ruger, a military facility built in the early 1900s. Like the lighthouse, Fort Ruger is also listed on the National Register of Historic Places.


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