Separation of black sand

Black sand, what it is?

One may see on this picture that it appears actually black. Not always so. Sometimes it is redish or dusty orange or simple dusty. Most of times it appears darker than other types of sand. It is magnetic and one may see magnet on picture lifting and separating black sand from the rest. Its specific gravity is higher than usual silica sand or quartz sand for 3-4 times. It consists of magnetite and hematite and other heavier minerals. Not all of them have same magnetic attraction.