Because beaches are composed of the same rocky material as the adjacent land, the color of the beach is determined by the rocks of that area. This compound can be colorless, milky white, brown, or light pink. A combination of these colors gives our beaches their characteristic color of light tan. In some parts of the world, such as Hawaii, there are black sand beaches composed of pulverized lava. In Bermuda, coral remains color the sand pink.
Sand is rare on the deep ocean floor, which is mainly mud.
Most sand is a product of the weathering of rocks on land areas inland from the beaches. Weathering processes such as rain, freezing and thawing, and chemical reactions break down the rocks into fragments, and streams and rivers transport these particles to the oceans. Once at the seashore, they are moved by offshorecurrents and waves from one area to another. By a process of natural sorting, the heavier rocks will tend to sink to the bottom layer of the beach, while the lighter particles will be found on the top layer. Hence a beach profile is never the same from one minute to the next.