-Al- is a silvery white metal with atomic number 13. It is the most abundant metal found in the Earth's crust, and the third most abundant metal today. Aluminum has very low density and it's resistant to corrosion. It is also lightweight, durable, malleable, and ductile. Aluminum is very important in the transportation and construction industries, and especially in the aerospace industry. Aluminum is one of the most widely used metals today.