Aluminium is the most used metal after iron. It has the advantage that it is about 3 times as light as iron, making it a perfect material for airplanes. Aluminium is the most abundant metal found naturally on earth, but is nonetheless very difficult to extract because it is very reactive.
Fertilizers made from potash, phosphate rock, sulphur and nitrogen enable agriculture to flourish. Phosphates and potash (salts that contain water-soluble potassium) are both extracted directly from minerals. Phosphorus is important for the development of the roots, flowers, fruits and seeds. Phosphorus is mined from limestones and mudstones with a high phosphate content.