Rock is the consolidated part of the earth crust, which weathers to release the mineral particles from which soil is formed.
The mineral particles form the skeletal framework of the soil. Rocks can also be said to be hard compact mass, which is made up of clusters of either primary or secondary minerals.
Primary minerals are those that are natural in nature; they are the original minerals.
Some primary minerals are quartz. (SiO2) found mostly in acid rocks, olivine which consists of (Mg. Fe)2SiO2, pyroxene, hornblende, Biotite, muscovite and feldspar that consist of NaKALSiO8, NaALSiO3O8.
On the other hand, the secondary minerals are made up of particles worn out from original minerals, which have mixed up with other elements.
The secondary minerals exist in form of oxide (like magnesium, iron and aluminium), suiphates and carbonates of iron, magnesium and calcium, and clay minerals (like silicate clays and the hydrous oxide).
Geologists study rocks and its formation. Geologists are scholars who undertake the study of rocks and the earth’s crust.