What are rocks?

Rocks are usually called loose or dense masses that form the crust and become sources of minerals. They consist of various minerals, and may also contain fragments of other rocks. Their structure and composition directly depend on the geological processes occurring on the surface of the earth's crust, as well as within it, which form them. We will tell you what rocks are, what they are and what they consist of.

Types of rocks

It is customary to distinguish three main types of rocks:

  • igneous;
  • sedimentary;
  • metamorphic.

The igneous rocks received this name because this species includes masses formed from molten magma in the process of its cooling. Their structure is due to the rate of magma hardening. This type is the most common rock in the world - granite, which is widely known as a building material. Another known volcanic rock is basalt, which, when ground, is used as a facing stone.Another common type of igneous rocks, pumice, is also used as a grinding material.

Sedimentary rocks make up a large part of the earth's crust (70%) and occur only on its surface in the process of sedimentation. If you are interested in what is related to sedimentary rocks, then you should distinguish their subspecies:

  • detrital (sand, crushed stone, clay);
  • organogenic (phosphate, combustible minerals, limestone);
  • chemical (sodium and potassium salt, silica).

Metamorphic rocks are igneous and sedimentary rocks, which under the influence of chemical solutions, pressure and temperatures undergo various changes in the bowels of the earth. For example, granite is converted into gneiss, clay into shale, limestone into marble.

What are rocks composed of?

Igneous rocks consist of large mineral crystals. Granite contains the following components:

  • potassium feldspar;
  • mica;
  • quartz;
  • sour plagioclase.

Granite layer contains a variety of non-ferrous and precious metals.

Basalt is a rock that consists of small crystals and contains a large amount of iron.

As for sedimentary rocks, their varieties also differ in composition and structure.For example, clastic rocks contain fragments of various rocks and, depending on their size, are divided into small-clastic, medium-clastic and large-clastic.

Organogenic rocks consist mainly of the remains of animals and plants that have accumulated at the bottom of oceans, lakes and seas over tens of thousands of years. Chemical sedimentary rocks distinguish their formation from aqueous solutions of mineral substances.

Metamorphic rocks, which initially are igneous or sedimentary, retain their chemical composition without significant changes. However, they are the result of the transformation of these species with compaction texture.