Various minerals can be found in the crust of planet Earth. Some of these minerals, such as gold (Au), are elements. Elements consist of only one type of atom.

Some minerals, such as quartz (SiO₂), are compounds. Compounds consists of atoms from more than one element. The image on the right shows quartz crystals.

A single rock type usually contains 3–5 different minerals. For example, granite consists of three different minerals: white quartz, red or grey feldspar and black schist. The edges of pavements and walkways are usually made from granite. 

Mineral-based soil types include till, gravel, sand and clay. In till, all of the original substances are still completely mixed and separate from one another. Gravel is a finer material than till, whereas sand is finer than gravel. Clay is the finest soil type.


Soil types: Fine sand, gravel, coarse sand and clay.