Not too far from South Point (the southernmost point in the United States) on Hawaii's Big Island is Papakolea Beach. This green-sand beach sits at the mouth of a bay on a tuff ring (the site of a volcanic eruption) that was formed some 49,000 years ago. Papakolea Beach can be reached only by a vigorous downhill hike, and upon arrival, travelers will find grains of sand that are almost pure olivine, with shades of green across the color spectrum. The olivine came from ancient lava flows of Pu'u Mahana.

Source: Travel and Leisure