There are many wondrous, enigmatic and fascinating attractions on the Big Island of Hawaii, some better known than others, many out of the way and generally off the beaten track. Tour Guide Hawaii has produced an encyclopedic collection of the most up-to-date information, presented as short GPS-cued videos, in an app downloadable to iPhone and iPod Touch that covers the entire Big Island, highlighting the popular and the uncrowded, the famous and the secluded, the adventurous and the relaxing.
The Colored Sand Beaches of the Big Island of Hawaii
Our Big Island is geologically quite young and the landscape is immature, so our beaches tend to be smaller than those on the older islands, and are therefore all the more precious. What the Big Island has that some of the other islands lack, though, are beaches with spectacularly colored sand…white sand, black sand, green sand and even grey sand.
The creamy white sand beaches of picture postcards and hapa haole songs result from the accumulation of small particles of coral reef and crushed shell fish shells. As the reefs grow, wave and storm action break it into small pieces and many fish, such as the parrot fish and the humuhumunukunukuapua’a munch the coral, spitting-out sand sized particles, and the coral they swallow comes out…er…the other end as sand-size pellets of sandy waste. In this way, one coral-eating reef fish can produce up to a ton of white sand a year. Because our white sand beaches result from physical degradation of soft, biological material, the sand grains tend to have rounded edges. Thus, unlike sands derived from rock and mineral sources, such as the California beaches, they do not stack well and tend to produce poor sand castles.
Beautiful white sand beaches occur all over the Big Island, but are biggest and best developed on the Kona and Kohala coastlines, as coral reefs prosper best on the lee-side of the island. Prime examples of white sand beaches include Anaeho’omalu, Hapuna, Waialea and Makalawena Beaches. Snorkeling at these white sand beaches is a joy—the water is a brilliant turquoise due to the amount of light reflected back into the water by the sandy shore bottom. However, this sandy bottom itself is relatively barren of life, so if seeing fish is your main snorkeling goal, be sure to choose a beach with a nearby reef, such as Waialea Beach, since the fish live in and around reefs and rocky cliffs.
Black sand beaches are strange and spectacular, and, because of their thermal properties, are warm even on a chilly day (Oh, yes, we do have chilly days here in Hawaii–in mid-winter temperatures can dip into the low 70s and even rarely the upper 60s!). In fact, it is the black sand beaches of the Big Island that are the choice among egg-laying female Hawaiian green sea turtles for laying their egg clutches on, precisely because of their warmth.
Black sand beaches result from the fiery, explosive mix of hot liquid lava entering the ocean. The skin of the lava stream is instantly chilled as it flows into the water and then blasted off when the ocean water flashes to steam. Black sand also results from mechanical action during the natural physical erosion of the basalt (the name for the rock our lava becomes once it cools). You’d think that sand forged in the volcano would be tough and enduring, but in truth, it’s very, very fragile and black sand beaches do not last long over time. For this reason, although the sand is beautiful and rare, we ask you not to take any home with you.
Black sand beaches occur all over the island… two of the largest are on the north end of the island, crossing the mouths of Waipi’o and Pololu Valleys, respectively. These are not visited as often as some of the others as both entail something of a hike down into the canyons. What once must have been a heart-achingly beautiful, large black sand beach fronts Hilo Town right on Hilo bay, but much of it has been eroded, polluted and degraded by industrial encroachment or simply paved over as a result of urbanization. By far the most popular black sand beach is at Punalu’u. Not only is the beach lovely, inviting and easily accessible, it’s almost guaranteed that the visitor will see Hawaiian Green Sea Turtles basking on this beach. The youngest and most vibrant black sand beach is Kaimu Beach at the end of the Kalapana-Kopoho Road. Kaimu beach, lovely if barren, is a crescent of sand that lies at the end of an unforgiving expanse of basalt from the 1990 flows. The old beach and the fishing village of Kalapana that once stood here are long gone, buried under 50-75 feet of lava—an unimaginable catastrophe
Snorkeling at the black sand beaches can be dark and mysterious, as little light is reflected back into the water from the sandy bottom, but the bouldery nature of the off-beach sea floor assures the prospect of abundant life and many reef fish. Be aware…because black sand beaches mostly occur on the youngest, and therefore most exposed, portions of our island, many are characterized by big waves, strong currents and nasty rip tides. Swim only where you see others swimming, and only when a life guard is present.
Wild, surreal, enchanting, the Big Island’s green sand beaches are a rare geologic occurrence that appear in only a few choice spots on our island and almost nowhere else in the world. Although they take a little effort to get to, you should not travel all the way to Hawaii and not see these jewel-like beaches.
The green sand is composed almost entirely of the mineral olivine, or peridot as the gem quality crystals are known. These crystals precipitate out of the molten lava while it sits in the magma chamber reservoir before it erupts onto the surface. The liquid lava is melted from rocks at great depth within the earth; the chemical composition of the melt is at equilibrium at extremely high pressures and temperatures. As the magma migrates upward, many miles, through the Earth’s crust, it cools and pressure decreases; this causes crystals to precipitate from the melt. In magmas world wide, olivine is almost always observed to precipitate out first.
In Hawaii, lavas migrate up to the surface so quickly, and then are expelled from the magma chamber onto the surface so quickly, that usually they have little time for many crystals to form. But when lava does sit in the magma chamber awhile, the olivine crystals do precipitate, and they slowly settle to the bottom of the melt. As liquid lava begins to erupt onto the surface, much of the olivine is left behind in the residual liquid. Thus, lavas erupted from the latest stages of these magma chambers sometimes are enriched with crystalline olivine. Since late stage magmas are also relatively cooler and less fluid, their eruptions are more explosive and they tend to form more spatter cones than flows. The green sand beaches of the Big Island result where the ocean has breached one or another of these spatter cones, and the winnowing action of the waves has washed away all the particles except for the relatively denser olivine grains.
There are tiny green sand beaches all along the southern coastline on either side of South Point, but the largest and most accessible is Mahana Beach on Papakolea Bay at South Point, reached by a moderate hike of about 2 ¼ miles along the wild coastline northeast of South Point, following an old 4WD two-track. Because of the unique sand color, snorkeling at the Green Sand Beach is a must…underwater pictures, if you are equipped with a suitable underwater camera, are quite stunning. Just be careful of the treacherous currents, rip tides and big waves. This is the wild and open ocean and this side of the island is completely unprotected. Once again, due to its rarity and the irreplaceable nature of this resource, we ask that you enjoy our Green Sand beaches, but don’t take any sand home with you.
Warm, comfortable and inviting, grey sand beaches result from mixing of black sand particles with white sand along a stretch of beach and as such, are represented by a continuum of grey hues. In fact, many Big Island beaches probably fit more with a definition of grey sand beach than properly occupy either of the two distinct end member compositions, black sand or white sand beach. Ho’okena, Kahalu’u and Honomalino are three of the largest and most popular grey sand beaches on the Big Island. There is one entirely unique beach, Ke-awa-iki, which today is a dominantly black sand beach, but the black sand has incompletely mixed with the older white sand on the southern portion of the beach, leaving a stretch of strange, but oddly artistic, piebald black and white sand.
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All media copyright 2010 by Donald B. MacGowan. All rights reserved.