The elements or compounds, which occur naturally in the Earth's crust, are known as __________.
minerals
The elements or compounds, which occur naturally in the Earth's crust, are known as minerals. Minerals are substances that are formed naturally on the Earth. These are usually solid, inorganic, have a crystal structure, and form naturally by geological processes. They can be made of a single chemical element or more usually a compound. The study of minerals is called mineralogy.