Formations consisting of minerals and arising inside or on the surface of the earth under certain geological conditions are called “rocks”. They formed more than 4600 million years ago and have a different structure and colors.
By their origin, rocks are divided into three types: sedimentary, igneous, and metamorphic.
The first group of minerals is formed on the surface of the Earth's crust. Rocks of this species are formed as a result of the accumulation of precipitation on land and in water bodies and their subsequent subsidence under the influence of gravity. Depending on the method of education, they are divided into:
- Chemical rocks. This group of minerals is formed from aqueous solutions of nutrients, as well as from the remains of animals and plants accumulated at the bottom of the oceans, lakes and seas. This includes table salt and potassium salt deposited at the bottom of reservoirs, silica located in hot springs, as well as combustible minerals (oil, gas, coal), phosphorites and limestones (limestone, chalk, etc.). Many minerals in this group have a layered texture.
- Fragmented. They are formed as a result of weathering or movement of parts of rocks by wind, glacier or waters and their subsequent accumulation. As a result, they are further crushed and crushed. Small, medium, and large-detrital rocks are found in size. Such minerals include pebbles, gravel, sand, gravel, clay.
Igneous rocks arise as a result of crystallization of molten matter located in the bowels of the Earth - magma. They make up more than 65% of the total earth's crust and are the most abundant minerals.
Magma is a silicate composition saturated with gases and water vapor and molten to 1200 degrees. It comes to the surface of the earth solely under the influence of various geological factors, where it cools and crystallizes and forms rocks, such as, for example, basalt, granite, olivine, pyroxenes, amphiboles.
Magmatic minerals are divided into intrusive and effusive.
- Intrusive rocks are located in the bowels of the earth at shallow depths. They are distinguished by good crystallization and, depending on the geometry and shape, are divided into batholiths (have large sizes), dikes (have a tubular structure and are formed as a result of filling cracks), veins (thin and long in length).
- Intensive formations occur when magma exits and consists of un-crystallized volcanic glass. Among the rocks of this type, huge basalt plateaus and lava naty stand out.
Depending on the depth at which magma lies, there are three groups of igneous rocks:
- Plutonic - are formed in the lower part of the Earth's crust (partially or completely). Granite belongs to this type of minerals.
- Volcanic - are formed on the surface. This includes minerals like andesite.
- Hypabyssal - occur when magma fills cracks in existing rocks. This group can include pegmatitis.
Metamorphic rocks. This type of mineral is a magmatic or sedimentary mineral, which, being in the bowels of the earth, undergo significant transformations. Changes that occur as a result of temperature drop, high pressure or chemical interactions cause the appearance of a new texture and structure of rocks, without affecting its chemical composition. As a result, one mineral, without melting and dissolution, is converted to another, harder and more stable. For example, limestone turns into marble, granite into gneiss, sandstone into quartz.
Thus, rocks of metamorphic, sedimentary, and igneous origin together constitute the thickness of the earth's crust. These minerals are the main source of minerals used by man for material production.