Geology And Geophysics

Understanding the three Basic Types of Rock



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Rocks can be one of the most fascinating things in all of nature to study, because there is such a wide variety in them. If you are interested in rocks you will find different ones almost no matter where you are in the world, and there is always going to be a lot of them to study. When geologists try to categorize rocks, they basically put them into three different categories, or types. The three basic types of rocks are: (1) Igneous Rocks, (2) Sedimentary Rocks, (3) Metamorphic Rocks.

First, Igneous rocks are crystalline solids which form directly from the cooling of magma, which is an exothermic process (this essentially just means that it loses heat) and involves a phase change from the liquid to the solid state. The earth is made of igneous rock, at least at the surface. Igneous rocks are usually given names based upon two things: composition (what they are made of) and texture (how big the crystals are).

Sedimentary rocks are called secondary, because they are often what results from the accumulation of small pieces broken off of pre-existing rocks. There are three main types of sedimentary rocks: Clastic, Chemical, and Organic, and these are usually classified by the source of their sediments. Limestone, chalk, and sandstone are all different types of rocks that would be considered sedimentary.

The Metamorphic rocks get their name from "meta" (change) and "morph" (form). Any rock can ultimately become a metamorphic rock. All that is required is for the rock to be moved into an environment in which the minerals that make up the rock become unstable and out of equilibrium with the new environmental conditions. The metamorphic changes in the minerals always move in a direction that is designed to restore equilibrium. Common metamorphic rocks include slate, schist, gneiss, and marble.

So rocks are a fascinating field of study, as the depth that you can go into them can be mind-blowing. There are different styles and varieties of rocks all over the world, so you will never run out of things to look at no matter where you are. Generally speaking, there are three different types of rocks, and those are igneous rocks, sedimentary rocks, and metamorphic rocks. Rocks are naturally occurring aggregates of minerals, and if you want to understand the earth and how it works, then you would be wise to take up the study of rocks.

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