Feb 17, 2021 · Sand dunes are often mined for the mineral quartz found in the sand. Sand occurs naturally when rocks and other minerals break down. Although the exact makeup of sand varies greatly from place to place and depends largely on the type of rock found in a given location, its most common primary component is the mineral quartz. The most highly prized sand for mining is known as unbounded sand, which contains smaller amounts of clay and other impurities than other sands