Papakolea Beach, also known as Green Sand Beach or Mahana Beach, is a green sand beach located near South Point, in the Kaʻu district of the island of Hawaii. It is one of the only four green sand beaches in the world, the others being in Galapagos Islands and one in Norway.

The olive-like color of the sand comes from the presence of a greenish, semi-precious stone named olivine that comes from the cinder cone of Pu’u Mahana, a 49,000 year-old volcano on Mauna Loa’s southwest rift, against which the beach is located.

The erosive force of the ocean washing into the base of Pu'u o Mahana cinder cone has extracted olivines out of the cinder and deposited them on the beach, giving the sand a green tint.

Puʻu Mahana lat erupted 49,000 years ago. Since then, the cinder cone has partially collapsed and has been eroded by the ocean. The cinder cone is rich in olivine, a silicate mineral containing iron and magnesium. Olivine is a common mineral component of Hawaiian lavas and one of the first crystals to form as magma cools.