Types of rocks


  • 1 rocks
  • 2 fiery rocks
    • 2.1 Classification of igneous rocks
    • 2.2 Characteristics of fiery rocks
  • 3 sedimentary rocks
    • 3.1 Types of sedimentary rocks
    • 3.2 Characteristics of sedimentary rocks
  • 4 metamorphic rocks
    • 4.1 Types of metamorphic rocks
    • 4.2 Types of transformation
  • 5 types of rocks video
  • 6 References

The rocks

Rock ( in English: Rocks) are solid blocks made up of metals and semi - metals ensue in the form of crystals of varying size, some large size can be distinguished by the naked eye, and some microscopic size, and some of the rocks are free of crystals. The rocks are divided according to the way they are formed into three types: fiery rocks, sedimentary rocks and metamorphic rocks. [1]

Fiery rocks

Fiery rocks (English: Igneous Rocks) are rocks formed as a result of the hardening or freezing of molten material in the ground ( magma ), due to the gradual and continuous cooling, or rapid and sudden cooling. [2]

Classification of igneous rocks

Fiery rocks can be classified based on several foundations, including: [2]
  • Silica ratio: Fiery rocks are divided according to the silica content in them into:
    • Acid rocks: These are fiery rocks that have a silica ratio of more than (66%), including: granite and granodiorite rocks.
    • Medium fiery rocks: These are rocks in which silica ranges from (52 ​​-66%), including: diorite and cyanite rocks.
    • Basal fiery rocks: they are rocks whose silica ranges from (40-52%), including: basalt rocks and gabbro.
    • Fire rocks above the bases: These are rocks where the percentage of silica is less than (40%), including: peridotite rocks and donuts.
  • The site of formation: The igneous rocks are divided depending on where they formed into: [2]
    • Underground fiery rocks or plutonian rocks: rocks solidified at great depths below the surface of the earth as a result of gradual and continuous cooling under high pressure, and the presence of volatile materials, characterized by their rough texture that consists of large-sized mineral crystals that can be distinguished by the naked eye, examples of which are: granite and diorite , And gabbro.
    • Fire igneous rocks (volcanic): These are rocks solidified near the surface of the earth as a result of rapid cooling, and its texture is either fine-grained (i.e. contains small mineral crystals), or glass (i.e. it does not contain mineral crystals).
    • Interfering fiery rocks: These are fiery rocks that formed in a central region that is not deep, nor shallow, and whose texture is medium granular, including: neo rocks (incisors), and dam rocks.

The properties of fiery rocks

Some of the properties of igneous rocks include: [3]
  • Do not arrange compact layers.
  • The size of the crystals that make up it depends on the speed at which the rocks cool. When the cooling is slow, the size of the crystals is large.
  • It does not contain pores and is therefore impermeable to water.
  • Resists erosion , so it erodes very slowly.
  • Contains no fossils.
  • Contains silica, magnesium and iron.

Sedimentary rocks

Sedimentary Rocks are rocks that are formed from granules that were separated from pre-formed rocks as a result of various factors, they were deposited, and their parts were joined together. [4]

Types of sedimentary rocks

Sedimentary rocks are classified into three main types, which are: [5]
  • Clastic Sedimentary Rocks: Young rocks are formed from crumbs of other rocks that were separated from each other due to mechanical weathering processes without being subjected to chemical changes, and then solidified and fossilized again, and some were joined by pressure, for example: conglomerates, rocks Brescia, silt rocks, sandstone , and clay stone .
  • Chemical Sedimentary Rocks: They are sedimentary rocks that form when water evaporates in arid lands and leaves behind dissolved minerals . Examples include: charts, dolomites, gypsum, limestone , and rock salt.
  • Organic Sedimentary Rocks: These sedimentary rocks formed as a result of sedimentation of animal remains, such as: bones and shells that contain calcium salts, and plant residues on the sea floor, and with the passage of time they hardened, and their types: amber, coal or coal Limestone, anthracite, peat and lignite.

Sedimentary rocks properties

Among the characteristics of sedimentary rocks are the following: [6]
  • It contains plant and animal fossils.
  • It consists of several layers.
  • It is characterized by fragility and rapid wear due to erosion and weathering factors.
  • It contains many pores, which enables it to store groundwater between its layers.
  • Neem signs are shown on it, which are formed due to the continuous movement of marine waves and their collision with rocks .

Metamorphic rocks

Metamorphic rocks ( in English: Metamorphic Rocks) are sedimentary rocks or bullets came under pressure and heat of various chemical processes; which affected the chemical composition and texture, and the type of metal component to them. [7]

Types of metamorphic rocks

The metamorphic rocks are classified into two types K: [7]
  • Fragile rocks: They are rocks that have been transformed as a result of exposure to heat and direct pressure, and appear as if they are arranged in layers, the most important of which are gneiss, schist, slate, and filet.
  • Non-furtive rocks : They are metamorphic rocks that are not arranged in layers. Examples include quartzite, hornfulls, marble, and neopacolite.

Types of transformation

The conversion of rocks to new rocks occurs in several ways, including: [8]
  • Contact or thermal transformation: It results from a burst of fiery masses burning rocks, which change their nature and the arrangement of their crystals, as happens when the quartz turns into a corazite rock.
  • Domain or dynamic transformation: It is the most prevalent type of transformation, and occurs when the rocks are exposed to extreme heat and pressure, which leads to the destruction of some or all of the original tissue of the rocks, and the formation of new minerals and tissues, as happens when the mud rock changes into slate rock.
  • Destructive transformation: A transformation that occurs when rocks are exposed to high pressure during tectonic movements, which leads to the breakage and milling of the constituent minerals, and the resulting rocks appear as luminescent as in myelite rock.
  • Burial transformation: It occurs when sediments accumulate over sedimentary rocks, which causes them to overheat and subject to intense pressure that alters their mineral composition and the tissues forming them.
  • Hydrothermal transformation: A metamorphosis that results from the exchange of metals between the solutions surrounding the rock and the rock itself when exposed to high temperatures. Examples include the entry of sodium and the exit of the element calcium when the basalt is converted to a sulfite rock.

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