Papakolea Green Sand Beach - Hawaii, big island
Papakōlea Beach
Located on the Big Island of Hawaii, Papakōlea Beach is one of the world's only green sand beaches. The beach was created by the eruption of the Mauna Loa volcano, which formed the cinder cone Pu'u Mahana. The name Papakōlea means "plover flats" and comes from the Pacific golden plover.
Green sand beaches are green because of the presence of olivine, a mineral that's rich in iron and is found in the lava that forms the sand:
Olivine
Olivine is a green, glassy crystal that's denser than the other components of lava, like ash, glass, and black pyroxene. It's one of the first crystals to form when magma cools.
Formation
When the lava cools, the olivine crystals separate and accumulate on the beach, giving it its green color.