Igneous Rock Types

Igneous rock is formed from magma that cools and hardens, which is mostly composed of silica (SiO2). But depending on the composition of the magma, igneous rocks can vary in terms of color, density, mineral composition and texture. Igneous rock types are then identified and classified based on these characteristics.

The difference in color is mainly due to the presence of minerals. Rocks https://www.batucollection.com/ that contain many colored minerals are called ultramafic, for example, peridotite, which forms the earth’s casing. Common, dark-colored rocks are called mafic, such as basalt and gabbro. Furthermore, rocks that are light in color are called felsic, for example granite.

The difference in texture occurs due to the difference in the cooling rate of the magma. The cooling rate of magma, depending on the location of the magma, can occur in the magma chamber, in the magma channel (corok) and on the surface of the earth. Generally, the deeper the magma is, the slower it cools so that the mineral crystals have enough time to grow before the magma solidifies, and the rock will have a coarser texture. Here are three types of rocks that fall into the category of igneous rocks.

1. Plutonic Igneous Rocks
Plutonic igneous rocks are rocks that are formed from magma that freezes deep within the earth and consists only of crystals. The process of cooling deep igneous rocks is very slow, therefore perfect crystallization occurs. These deep igneous rock crystals are large and coarse. The plutonic igneous rock group includes granite, gabbro, diorite, and syenite.

2. Igneous Alley
Meanwhile, alley igneous rocks are formed from magma that freezes in corrodes or alleys, so that they are closer to the surface of the earth. The process of cooling magma to form igneous rock occurs more quickly, with less perfect crystallization. As a result, these rocks have large crystals, small crystals, and even do not crystallize. The igneous rock group includes granite profir, gabbro prophyte, syenite prophyte, and phosphoric granite.

3. Volcanic Igneous Rocks
Also called external igneous, molten, or extrusive rock, this type of igneous rock is created from magma that rises to the surface of the earth (lava). If it is outside the surface of the earth, then the cooling process of the lava will take place very quickly and it is unlikely that the crystallization process will occur. Volcanic igneous rocks include rhyolite, andesite, trachit, basalt, obsidian, and pumice.Types of Sedimentary Rocks