The earth crust which is the outer solid shell of the earth belongs to the rocky soils. These soils are composed of inorganic solids, that is compounds that do not depend on the presence of living organisms for existence. Minerals are also inorganic solids but they differ from rocks in their arrangements.
About 98 percent of the total crust of the earth is composed of eight elements like oxygen, silicon, aluminum, iron, calcium, sodium, potassium and magnesium and the rest is constituted by titanium, hydrogen, phosphorous, manganese, sulphur, carbon, nickel and other elements.
Elements by Weight (%)
- Oxygen- 46.60
- Silicon -27.72
- Aluminium- 8.13
- Iron -5.00
- Calcium – 3.63
- Sodium – 2.83
- Potassium – 2.59
- Magnesium – 2.09
- Others – 1.41
Minerals such as coal, petroleum and natural gas are organic substances found in solid, liquid and gaseous forms respectively.
