Joulters Cay, Andros Island, Bahamas
Oolites are tiny concentrically laminated spheres or rods. In waters super-saturated with calcium carbonate, the grains accrete or grow around a nucleus, a bit of shrimp feces or a tiny shell or rock fragment.
Oolites accrete or grow larger as they are agitated by the waves, tides or currents. They form on the warm Bahamas Platform, in Great Salt Lake (a saline lake), and elsewhere.
Further information on ooids may be found at Simm Sepp's Blog, Sand Atlas.