Iron, for example, is widely used in building structures because of its high tensile strength and ability to support heavy loads. Aluminum is a lightweight, corrosion-resistant metal used in aircraft, ships and automobiles. Copper is an excellent electrical and thermal conductor and is used in the manufacture of electrical cables and water supply systems. Zinc is used as a protective coating against corrosion and oxidation. Silver and gold are precious metals, used in jewelry and electronics. Metallic materials can be shaped industrially by various processes, such as casting, forging, drawing, rolling, machining or welding. They can also be combined with other materials such as carbon, silicon and boron to create alloys with specific enhanced properties for industrial applications. It is important to note that some metals such as mercury, lead and cadmium can be toxic to humans and the environment.