Minerals and Rocks
The earth is composed of various types of elements. These elements are combined together to form minerals in the earth’s crust.
Mineral is a naturally occurring inorganic substance, having an orderly atomic structure, definite chemical composition and physical properties. The study of minerals is called mineralogy. There are mainly six major mineral groups, with which most of the mineral groups are associated. The major mineral groups are Feldspar, Quartz, Pyroxene, Amphibole, Mica, Olivine, etc.
Minerals are classified into the categories of metallic, non-metallic and energy minerals.
The aggregate of one or more minerals are called rocks. The earth’s crust is composed of rocks.
Rocks are formed by the combination of homogenous substances. Majority of rocks consist of several minerals.
On the basis of their formation, rocks can be grouped into three major categories.
These are igneous rocks, sedimentary rocks and metamorphic rocks.
Igneous rocks are solidified from magma and lava.
Sedimentary rocks are the result of the deposition of fragments of rocks by the exogenous processes.
Metamorphic rocks are formed out of the existing rocks which are undergoing the process of recrystallisation.
Rock cycle is a continuous process through which old rocks are transformed into new ones.
Thus, rocks and minerals form an important component of the earth’s crust.