Grains of sand are tiny particles that make up beaches, deserts, and riverbeds. They are formed through the weathering and erosion of rocks over thousands of years. Most grains are made of silica, which comes from quartz, but they can also be composed of other minerals. The size of a grain of sand typically ranges from 0.0625 mm to 2 mm in diameter. Sand grains can vary in color, shape, and texture depending on their mineral composition and the environment in which they are found. For example, beach sand is often lighter in color due to the presence of shells and coral, while desert sand can be darker and more uniform. These grains play a crucial role in ecosystems, providing habitats for various organisms and influencing soil composition.