The different types of Stones are obtained from the quarries and it is a natural material for construction purposes. We use it to construct different components of building such as retaining walls, foundations, lintels, roofs, and floors, etc and also for the construction of bridges and dams.

Stones are obtained from rocks and rocks form in the portion of the earth crust having no defined chemical composition and also have no definite shape and sizes.

Stones are classified into three main different types depending

1- Geographically

2- Chemically

3- Physically

1- Types of stones according to geographically
1- Igneous stones

From the solidification of the molten mass of lava, these stones are generally formed. They are laying below or above the earth surface.

  • It is formed after the colling of lava (magma).
  • It has crystalline glossy or fused texture.
  • Metamorphic or Igneous rocks make up to 90 to 95% 16 km of the top Earth’s crust by its volume.

Igneous rocks are divided into two categories

1- Intrusive

2- Extrusive

Intrusive Igneous rock

When magma is trapped inside the (deep) Earth those intrusive igneous rocks are formed.

  • Have a coarse-grained texture.
  • Need a very long time to grow.

Extrusive Igneous rock

Those rocks are formed when the magma cools near the earth surface.

  • Fine-grained or even glassy texture
  • When bubbles are trapped inside they formes vesicular texture

2- Sedimentarynrocks

These rocks are formed due to the settling of water from the deposition of clay and sand in the earth surface. Water carries sand, clay and makes a layer of them on other stones or surfaces which gradually becomes a rock itself. That is a sedimentary rock. These are also called the stratified because these rocks are formed in layers.

We further divide it into three more main types

1- Clastic sedimentary rocks

2- Chemical sedimentary rocks

3- Organic sedimentary rocks

Clastic sedimentary rocks

Due to mechanical weathering debris, these rocks are formed such as

1- Siltstone

2- Breccia

3- Conglomerate

4- Shale

5- Sandstone

Chemical sedimentary rocks

when dissolved materials precipitate from the solution, these rocks are formed such as

1- Iron ore

2- Flint

3- Dolomites

4- Rock salts

5- Limestone

Organic sedimentary rocks

These rocks are from with accumulation of plant and animal debris, such as

1- Coal

2- Limestone

3- The Dolomites

3- Metamorphic rocks

Due to excessive heat and pressure, these rocks are formed in the earth and they have altered from their original structures. Suppose an igneous rock is placed very below in the ground for many years it will gradually change itself due to heat and pressure it had to bear and become metamorphic rock.

We divide these rocks into two basic types

1- Foliated metamorphic rocks

2- Non-foliated metamorphic rocks

Foliated metamorphic rocks

Slate, Phyllite, Schist, and gneiss are an example.

Non-foliated metamorphic rocks

Marble, hornfels, quartzite, novaculite are an example.

2- Types according to chemically composition

According to chemical conditions, we divide it into three other main types.

1- Siliceous rocks

These rocks are those which have chief constituent sand silica as in the form of quartz, granite.

2- Argillaceous rock

In these rocks, the principal constituents are clay or alumina as in slate and laterite, kaolin.

3- Calcareous rock

These rocks are those which contain lime or calcium carbonate as the main constituents. The limestone and marbles are examples of calcareous rock.

3- Types according to physical appearance

According to the physical condition, we divide it into two other main types

1- Stratified rock

These rocks are those which have a distinct layer and can be separated out into thin slabs. The limestone’s, slate and sandstone are the examples of stratified stones.

2- Unstratified rocks

These rocks cannot be easily split into thin slabs and also does not show any sign of strata it. The granite and marble are examples of unstratified rocks.

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