“Early Hawaiians built fires on the top as a navigational aid for canoes traveling along O’ahu’s south shore, a function now provided by the Diamond Head Light, built in 1917. The name “Diamond Head” dates to the 1800s, when British sailors digging around in the crater found what they thought were diamonds. They rushed into Honolulu with their newfound treasure, only to discover that the “diamonds” were really worthless calcite crystals – but the name stuck.”
