Sand is any earth material consisting of loose grains of minerals or rocks larger than silt but smaller than gravel. Geologists measure sand by shaking it through a very fine wire mesh or screen.
Magnetite is iron particles that are found in some coastal sand. This magnetite comes from volcanic ash from thousands of years ago.
Most grains of sand come from solid rocks that have crumbled away as the rock breaks down from forces of air, water, ocean waves and frost.
Geologists find many types of minerals in sand, but the most common mineral is quartz.