The sands of many tropical islands are snow white. Beaches in Hawaii can be white, black, green, or red. In Bermuda, sand is often pink. And most of the world’s beaches are a sandy brown. What creates those different colors? Why is some sand soft and fine, but other types feel rough? Where does beach sand come from, anyway? The sand found on a specific beach is created by its surroundings. It’s unique to that beach—like a fingerprint.
Most beaches get their sand from rocks on land. Over time, rain, ice, wind, heat, cold, and even plants and animals break rock into smaller pieces. This weathering may begin with large boulders that break into smaller rocks. Water running through cracks erodes the rock. In areas where it’s cold enough to freeze, water expands as it turns to ice. This forces the cracks open wider. The freeze-thaw cycle happens over and over again. Each time, gaps widen. Pieces break off. Over thousands of years they break down into smaller and smaller rocks, pebbles, and grains of sand.
Pounding waves and the ebb and flow of tides also make sand. These motions knock rocks, pebbles, and sand grains against each other. This action wears them down. It also smooths the rough edges. The smaller and rounder the grains become, the softer the sand feels.
Different minerals in rock weather differently. Some don’t hold up well. Others, such as quartz and feldspar, are much tougher. These two minerals last longer than others and make up a typical sandy beach. Quartz tinted with iron oxide appears light brown. Feldspar is tan. Together, they create the sand-colored hue of many beaches.