Green Sand Beach has to be seen up close to be appreciated. There are tons of green olivine crystals in the sand, which is pretty cool to see. You've got to hike to get there, unless you have a 4-wheel drive. The hike is easy, though. It's over uneven terrain, but it's basically flat, about 4 or 5 miles roundtrip from South Point. Just drive to the end of the road, past a few houses to the little bay where they launch boats, and park there. When you're facing the ocean there's a rough dirt road to the left (east) - that's the "trail".
By the way, when we went there was a sign on one of the houses saying you had to pay $5 to proceed any further. We ignored this, since we had read that it was a scam, and we had no problems at all.
Puu Mahana, Green Sand Beach, is located in the Kau' district. It is primarily located on the slopes of Mauna Loa, the world's largest and most massive active volcano on the southwestern part of the island. To get to this beach, one must either use a four wheel drive or hike six miles from South Point, Ka Lae, the southern most tip of the United States.
Volcanologist, Steve Mattox of University of North Dakota gives this explanation for such a spectacular one of a kind place.
"The beach formed by the erosion and concentration of olivine crystals derived from the surrounding cone. The volcanic cone is Puu Mahana and it is a tuff ring (a type of volcano formed by the interaction of magma and shallow groundwater). The cone is associated with the Southwest Rift Zone of Mauna Loa (although the cone is not right on the rift). Mauna Loa flow can contain abundant olivine crystals. As ocean waves crashed against the coast they wore away at the cone and made a small bay along the coast. The waves also removed the lighter grains of sand (made of volcanic ash) leaving the denser olivine crystals behind to form the beach. I do not know of another green sand beach. Olivine is common in basalt lava. A few crystals might be found in some andesite lava. It is never found in dacite and rhyolite lava."
Puu Mahana, Green Sand Beach, is located in the Kau district. It is located on the slopes of Mauna Loa, on the southwestern part of the island.
To get to this beach, one must either use a 4-wheel drive or hike about two hours (6 tough miles) from South Point, Ka Lae, which is the southern-most tip of the United States. The road down to Green Sand begins as a rugged jeep trail. Jagged rocks are everywhere. Be sure to wear good hiking shoes when doing the hike down. Take plenty of water. Follow the road for ten minutes to reach an area lush with green pastureland made possible by an ancient volcanic eruption. After another 35 minutes of walking, you'll arrive at an ancient cinder cone. The trail down from here is as treacherous as they come. Do not try to climb down the loose sand of the north side. On the south a break in the gnarled lava rock offers handholds and descends to a good trail which hugs the cliff, above gleaming black lava flats filled with the white ebb and flow of powerful waves. Expect heavy duty climbing and drops of four to five feet. Follow the trail down to the beach.
You should find the bay to be clear, lucid turquoise.
The olive-like color of the sand comes from the presence of a greenish, semi-precious stone named, appropriately enough, olivine. As ocean waves crashed against this coast they wore away at the cinder cone and made a small bay along the coast. The waves also removed the lighter grains of sand (made of volcanic ash) leaving the denser green olivine crystals behind to form the beach. Olivine is common in basalt lava.
One must always have an eye for car break-ins in Hawaii. Some visitors even leave their cars unlocked, and their glove compartments open to show that there is nothing to steal. That does not always deter the thieves however and you might find your locks smashed anyway just out of frustration I guess. Often tourists return to their cars to find that their trunk lock has been punched in. So take nothing to South Point that you could not do without.