Sand Overview
The sand along this 1-kilometer beach is almost entirely calcareous. It is composed of skeletal remains of foraminifera and fragments of coral, shells, and coralline algae.
Geographic Overview
Yonehara Beach on Ishigaki Island is part of the Iriomote-Ishigaki National Park. The beach is highly rated for its world-class, easily accessible snorkeling and pristine, clear water. It is celebrated as a top-tier marine sanctuary with a vibrant coral reef just meters offshore. The sand is entirely calcareous being composed of biogenic remains of foraminifera, fragments of coral, shells and coralline algae. Its gently curved white sandy shore is framed by lush coastal greenery, including the nationally designated Yaeyama Palm Groves.
Sand Location
See where this sand sample was collected on Google Maps.
Virtual Sand Tour
Explore an interactive map of Yonehara Beach on Google Earth.
Sand Gallery
This mixture of smooth edged, rounded, and irregularly shaped white, translucent white and light tan marine sand grains is accompanied by occasional darker marine sand grains. Somewhat rounded grains covered with evenly spaced finely dimpled tan spots are worn down forams, possibly Calcarina sp. A tan and white shell fragment is near the center to the right of two round smoothly worn off-white forams. A conical mollusk fragment with tan spots is near the center lower edge. A well-preserved off-white mollusk shell to the right of center lies below the cross section of a sea urchin spine fragment with a dark brown center.
In addition to smoothly worn round forams with indistinct markings and worn pieces of tan spotted fragments (possibly Calcarina sp.), a large off-white marine fragment with holes as evidence of bioerosion is at top left center above a partially visible translucent finger-like rod of a sponge spicule. A colorful pink and red marine fragment is present near lower right of center.
A centrally located sea urchin spine with parallel grooves and a smooth base is surrounded by a mixture of partially eroded white and off-white forams. Several irregular white coral grains with cavitations as evidence of bioerosion are present at the top and bottom right center in this view.
Several partially eroded light-tan forams fragments, some with linear arranged openings, are present in this view along with two centrally located conical micromollusk chards, one with brown linear striping. Between these two gastropods and also at lower right of center are white and partially translucent fragments of other microsnails.
A centrally located large mollusk fragment with brown parallel stripes next to a small micromollusk with brown parallel stippling is surrounded by fragments of coral and pieces of forams. A large sand grain with radially arranged chambers, possibly a Marginospora sp. fragment, is at right center.
This low magnification view shows a mixture of round light tan forams, a central micromollusk gastropod with parallel tan stippling, two large chalk white coralline algae rods, and sea urchin spines (top and left center). A large white rectangular grain with a circular raised center is a sea urchin spine skeletal plate.