Igneous rocks form when magma, which is molten rock, cools and crystallizes either at volcanoes on the Earth's surface or while it remains inside the crust. All magma originates underground in the lower crust or upper mantle, where intense heat causes the rock to melt.

 properties of Igneous Rocks

Characteritics of Igneous Rocks:

Fine-Grained and Course-Grained

Igneous rocks can be both fine-grained or coarse-grained. Fine-grained contains more but smaller components whole coarse-grained contains fewer but larger components. Fine-grained are extrusive rocks, while coarse-grained are intrusive rocks.

Felsic, Intermediate, and Mafic

Igneous rocks can also be felsic, intermediate, or mafic. Felsic are lighter in color and contains more silica and feldspar. Mafic on the other hand is darker in color and contains more magnesium and iron. Most extrusive are felsic while most intrusive are mafic. However, there are also rocks with has both properties of felsic and mafic. These kinds of rock are called Intermediate. 

 Types of Igneous Rocks

Uses of Intrusive Rocks

Intrusive rocks are commonly used for construction and sculptures. In addition, some igneous rocks, such as obsidian, are crafted into sharp tools for cutting. Granite, for instance, is often used for flooring due to its durability. Here are some notable places in the Philippines where igneous rocks have been used in construction.