Magnetite from Quality Magnetite, LLC - Thomasnet . Magnetite can be used in a wide array of industries including, but not limited to Coal Processing, Dense Media Separation, Water Treatment, Algae Harvesting, Heavy Aggregate, Fertilizers, Pigments and Paints, Ferrofluids and magnetorheological fluids, Magnets, Minerals in cosmetics, Abrasives, Fireworks and pyrotechnics, Toys, Magnetic