The soft white sand of Waimanalo Beach is primarily composed of smoothly worn grains of marine organisms including forams and bivalve fragments with occasional black and dark fragments of smooth basalt.
Geographic Overview
Waimanalo Beach is a secluded beach on the windward side of O’ahu with a backdrop of the majestic Koolaui Mountains. Part of a stretch of almost 5.5 miles of beach, Waimanalo Beach is known for soft white sand, clear waters for swimming, kayaking, and snorkeling and is ideal for sunbathing under its ironwood trees.
Sand Location
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Virtual Sand Tour
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Sand Gallery
This high magnification shows the distinct chambers of a light tan foram located in the center and to the immediate right of an oblique view of a similar foram along with other smoothly worn forams and white and tan coral fragments.
This mixture of smoothly worn marine sand grains includes off-white and tan coral fragments. A centrally located round large foram and a smaller round foram, both with visible internal compartments, are just below a tan and brown bivalve shell fragment.
The internal compartments of a partially worn off-white and tan striped mollusk shell near the center of this image is accompanied by worn fragments of round and oval forams and other light tan marine fragments. An off-white bivalve fragment with linear grooves is near the upper left of this image. The black sand grains are probably basalt.
Small and medium sized round sand grains are different forams showing some interal texture but too eroded to clearly show compartments. A white foot-shaped rectangular sand grain with subtle parallel linear grooves located to the left of center is a barnacle shell plate fragment. Mottled black and gray grains may be geological, possibly a form of basalt, and the centrally located pointed sand grain with a brown stripe is a smoothly worn bivalve chard.
This mixture of smooth sand grains includes several white and off-white forams that are round with poorly demarked internal structure. Some forams are tipped showing different degrees of side views. Mottle brown and off-white fragments of mollusk shell and black grains of basalt are also present in this sand sample.
Round partially worn forams are present in the center along with the oblique view showing the linear grooves of a sea urchin spine fragment. Other sand grains include brown stripped fragments of polished mollusk grains, light tan shell fragments, semi-translucent shards and black angular basalt sand grains.
Multiple white and off-white forams, some showing linear holes in lateral views, make up this sample along with smoothly brown and gray mollusk shell fragments.
A round foram with subtle visible internal compartments is present in the center to the immediate right of a black, likely basalt, sand grain. Several other forams are present in this view with a lateral view of one in the upper center showing linear parallel holes.
Elongated smoothly worn white marine fragments, one with holes and grooves as evidence of predation, are present in this sample along with round off white forams, some with subtle internal structure, dark brown mollusk sand grains, and mottled black and gray basalt mineral grains.