Samples of beach sand from Wailea Beach photographed under a microscope at various magnifications. Notice the scale in the lower right corner of the images. The sand is composed of a mixture of biogenic and volcanic grains. The biogenic marine grains are smoothly rounded as a result of the famous strong winds and waves of Maui. Marine grains include bits of sea urchin spines with longitudinal grooves, rounded foraminifera tests of single-cell organisms (forams), white fragments of smoothed coral, an occasional colorful fragment of a bivalve, and tiny black magnetite grains.