A mineral is a unique composition of elements. For instance, silicon and dioxide interact chemically to form quartz.
The most common mineral, feldspar, which makes up about half of Earth’s crust, is aluminum plus sodium, calcium, or potassium.
Minerals will separate from cooling magma and make their way through veins into surrounding rock, called ore.
Miners search for these veins to find the minerals they contain. Some veins contain single-element minerals such as copper.