Most bounder-sized meteors never reach Earth’s surface as they burn up due to friction with air. However, countless micrometeorites, no longer than a grain of sand, manage to reach the surface adding about 400 tons of matter to Earth each day. They are made largely of iron and nickel. Both of these elements are magnetic, so if you drag a magnet over the ground it will pick up some particles. Most particles will be dust from outer space.