Types Of Rocks

In general, any naturally occurring collection of mineral particles makes rock. The solid section of the Earth is made up of a variety of rocks that differ in texture, structure, permeability, occurrence mode, and degree of resistance to denudation. Rocks are categorised into three categories based on their origin: igneous rocks, sedimentary rocks, and metamorphic rocks. There are a few organic-based rocks that may or may not contain fossils, such as coal, peat, and so on.

Rocks

Rocks are mineral aggregates that have qualities that are a mixture of all the mineral traces. Rock types can be defined by any unique combination of chemical composition, mineralogy, grain size, texture, or other differentiating properties. Furthermore, each main variety of rock has its own classification system. Natural rocks come in a variety of shapes and sizes.

Natural rocks rarely have such straightforward qualities, and they usually show some fluctuation in the collection of attributes as the measurement scale changes.

Types of rocks

There are three different kinds of rocks:

1. Igneous Rocks
2. Sedimentary rocks
3. Metamorphic rocks

Igneous rocks

One of the 3 primary rock kinds is igneous rock. The settling and solidification of magma or lava produces igneous rock. Igneous rock can form either underneath the surface as intrusive (plutonic) rocks or above the surface as extrusive (volcanic) rocks, with or without crystallisation. This magma can come from partial melts of existing rocks in the mantle or crust of a planet. One or more of three mechanisms can produce melting: an increase in temperature, a drop in pressure, or a change in composition.

Characteristics

1. Primary or basic rocks are those that were once thought to be the original kind of rock and the source of materials for later forms of rocks.
2. These sorts of rocks do not contain any fossils.
3. Mineral deposits may be glassy or coarse in character, and these sorts of rock forms contain several mineral deposits.
4. The granular size of the rocks was based on the pace of lava cooling; for very fast cooling, the granular size shrinks, whereas for slow cooling, the granular size expands.

Sedimentary rocks

These rocks are found on about 70% of the Earth’s upper surface and are formed through a series of processes in which eroded materials are shipped by exogenic agents in the early stages and then deposited as unconsolidated debris or sediments at lower gradients and suitable climate conditions in the later stages. As a result of metamorphic erosion and deposition, igneous rocks (or some older sedimentary rocks) are referred to as sedimentary rocks.

Lithification is the process of converting materials waste or sediments into consolidated sedimentary rocks after they have been deposited in favourable conditions. The layer of several consolidated sedimentary rocks is then converted into a large bound of sedimentary rock structure through the cementation process.

Characteristics

1. Fossils are commonly found in these kinds of rocks.
2. Shale, Sandstone, and Limestone are the most common sedimentary rocks (More than 97 percent).

Metamorphic rocks

Metamorphic rocks are characterized by texture, chemical and mineral assemblage, and make up a major portion of the Earth’s crust. They can be generated simply by being deep beneath the Earth’s surface, exposed to extreme temperatures and the immense pressure exerted by the rock strata above them. Metamorphic rocks are formed by the alteration of existing rock types, a process known as metamorphism. Metamorphism literally means “changing of form.” The original rock is heated to temperatures between 150 and 200°C, with a pressure of roughly 1500 bars, resulting in significant physical or chemical changes or both changes.

Types of Metamorphic Rock

The 2 categories of metamorphic rock are as follows:

1. Foliated Metamorphic rocks: These rocks have been foliated by heat and pressure, giving them a layered appearance. Foliated metamorphic rocks include phyllite and gneiss.
2. Non-Foliated Metamorphic rocks: These rocks don’t have layers. Non-foliated metamorphic rocks include marble and quartzite.

Characteristics

1. Among the three sorts of rocks, it is the hardest.
2. These rocks don’t have any fossils in them.
3. These rocks are made up of all three sorts of rocks.
4. These rock types are most commonly found in the mountain ranges’ cores.

Conclusion

The minerals found in rocks, as well as their texture, are used to identify them. The minerals found in each form of rock are unique. A rock, such as quartzite, can be made up of grains of only one mineral kind. Rocks are much more often made up of a combination of minerals. The size, shape, and distribution of mineral grains are referred to as texture.