Titanium is obtained through mining its ores, mostly in the form of titanium oxide in the minerals rutile and ilmenite, from open pits. The titanium oxide in these minerals must first be purified, then converted to titanium chloride, before titanium can be obtained. Titanium is the ninth most abundant element in the Earth's crust, but its mining and processing must be managed with expense and environmental concerns in mind.
Titanium oxide was first discovered by the English clergyman William Gregor, although it wasn't identified until later by the German chemist M. H. Klaproth, who provided its name. The pure metal was not produced until early in the 20th century. The basic process used then to obtain titanium is still in use as of 2014.
Titanium has many useful qualities, but its expense limits its use. It is twice as strong as aluminum and only 60 percent heavier, making it excellent for lightweight applications where strength is required. It resists corrosion by seawater and other natural hazards and is therefore often used in the moving parts of boats. Its high strength and heat tolerance also makes it valuable in the construction of airplanes, rockets and missiles. It doesn't react to chemicals in the human body, so it is often used in implants such as artificial joints.