Why do metals occur in nature as compounds?

Metals tend to form compounds, also known as minerals. They are natural solids made from chemicals and crystalline structures. They are inorganic, which means they are not alive. Minerals are usually made up of several elements mixed with each other, although some, such as gold, are exceptions that are found in elemental form.
Geological processes take place underground, while pressure and heat tend to push rocks above the planet’s surface. When this happens, due to the presence of both oxygen and water, the stones break down in a process known as weathering.