Papakolea Beach, Beach on Big Island, United States

Papakolea Beach is a strand on Hawaii's Big Island featuring green sand created by olivine crystals that accumulated from volcanic activity. The beach sits along the coast beside Puʻu Mahana cinder cone and ranks among the world's rare green sand beaches.

Papakōlea Beach lies in a bay half-circled by Puʻu Mahana, a tuff ring of volcanic ash formed over 49,000 years ago and linked to the southwest rift of Mauna Loa. Since its last eruption the ring has partly collapsed and been eroded by the ocean. The USGS states the last lava flow in the area ended more than 10,000 years ago, and the surrounding rock still shows layers from earlier eruptions and flows.

Papakōlea comes from papa kōlea, Hawaiian for "plover flats", the land near the crater where Pacific golden plovers (Pluvialis fulva) are sometimes seen in winter. The beach is also called Mahana Beach after Puʻu Mahana, the tuff ring that half-circles the bay. The name is applied both to the beach and to the surrounding land area.

The beach lies about 3 miles (5 km) east of Ka Lae (South Point) and is legally reachable only on foot; the land belongs to the Department of Hawaiian Home Lands, which has restricted vehicles since 2016. Paths across the pastureland are cut by ruts over 8 feet deep from illegal driving. After the walk you must climb down the tuff ring to the sand.

Olivine is locally called "Hawaiian Diamond" and also occurs at Diamond Head on Oʻahu, but there it is locked inside lava rock and weathers away instead of gathering as sand. At Papakōlea the crystals sit in soft volcanic ash, so the sea frees them and leaves them behind.