Hawaii is a series of islands composed, primarily, of lava. Lava isn’t all the same. Two main types are A’a (ah-ah) and pahoehoe (paw-hoey-hoey). There is also a third type, but you’re not likely to encounter it as it forms during submarine eruptions, this is called ‘pillow’ lava.
The dynamics of a lava flow generally dictate which type of lava forms. A’a lavas are associated with high discharge rates and steep slopes, while pahoehoe flows are associated with lower discharge rates and gentle slopes. Geology aside, pahoehoe is usually darker and a’a tends to be lighter and brownish to reddish. The reddish comes from oxidation of the iron to iron oxide.
Pahoehoe tends to be smooth. You can generally walk on it without shoes. A’a on the other hand is chunky and sharp – think of the sound you’d make when trying to walk on it bare foot!
If you snorkel at Two Steps, only minutes from Horizon Guest House and adjacent to Pu’uhonua O Honaunau National Historical Park, or Place of Refuge, you’ll find yourself walking over smooth pahoehoe before entering the water.
When the lava is broken up into fine grains we end up with a black sand. However, when the mineral olivine is present in large enough quantities, and is packed into a sedimentary formation, natural erosion creates a green sand beach.
In the photo below is the ‘famous’ Green Sand Beach – also called Papakōlea Beach. This unique beach is located about two miles from the southern most point of the Big Island, South Point, and is approximately an hour’s drive south of Horizon Guest House.
Papakōlea Beach is one of only four green sand beaches in the world, the other three are in Guam, Galapagos Islands and Norway.
The cliff in the background of the photo is a loose, sedimentary formation containing a relatively large amount of olivine as fine crystals. The green crystals are mixed with black (lava) and white (coral/shells) sand and, as a result, some patches of sand are greener than others.
How to get there
To get to Papakōlea Beach involves a drive and a hike (but it’s well worth the extra effort).
- Take the road to ‘South Point’ between mile markers 69 and 70 on Hwy 11 (between Kona and Volcano Village). Drive to the small harbor at the end. On the left hand side there is a car park.
- Walk from the car park to the ocean and take the road to the left (facing the water, toward the east). Follow the road with the ocean on your right for approximately 2.5 miles. At this point you will be above the beach. Next, make your way carefully along the lava cliff on the west side of the bay.
Tip: Leave early and try to make the trip on a weekday to avoid the crowds.
You can see in the next photo how green the olivine sand is. There is also a lava rock with olivine occlusions, and a bracelet made from larger olivine crystals.
Fun fact! A type of olivine is peridot (also found in meteorites) and is a gem quality stone. Peridot is also referred to locally as ‘Hawaiian Diamond’. Found in only a fraction of the olivine deposits, it is the birthstone for the month of August – so happy birthday to all you August babies out there!
Strange but true! When lava is ejected into the air, it can form an usual solid lava that has an uncanny resemblance to petrified wood. These samples below came from the Hualalai mountain, which is the mountain you see when you land at the Kailua-Kona airport.
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