All metals come from ore deposits found in the Earth's crust. Raw ores bear little resemblance to familiar metals such as chromium or nickel. In most cases, the metals in the ores are not in the free, or pure, state. They are in chemical combination with other elements. They are combined with oxygen as oxides, with sulfur as sulfides, and with carbon and oxygen as carbonates.
Ores also contain earthy materials such as sand and clay.
These worthless substances are separated and discarded. Large ore deposits can mean great wealth to a country. The struggle for economic and political control of ores has gone on between nations for thousands of years. An industrial nation can process its ores to produce valuable metallic products. If a nation is not technically developed, it can sell its raw ores profitably to industrialized nations.