World Facts

What Is Andesite?

Andesite is similar to but different from Basalt, as it carries much lower levels of Iron and Magnesium.


Andesite is a unique, igneous rock that is formed as a result of volcanic activities. Specifically, igneous rocks are solidifications of volcanic lava or magma. The coloration of Andesite rock will vary in shades of light and dark greys, as well as the various shades of brown that can be seen in certain specimens. It is a mineral rock which can contain plagioclase feldspar minerals. These minerals include biotite, pyroxene, or amphibole. It is also a 'host rock' for the popular gemstone Andesine. Its gravity pull is 2.5-2.8, and it's predominately composed of Silicon Dioxide (Chemical Formula SiO2).


The name 'Andesite' is derived from the South American Andes Mountains where the rock was originally discovered. However, the rock forms from subduction zones all around the world. These zones can be found in Central America, Mexico, Japan, Indonesia, the Philippines, New Zealand, the US Pacific Northwest, and the Caribbean alike.


Andesite rocks will form in regions above subduction zones. This formation usually occurs after oceanic plates melt amid the subduction zone, as the melting serves as a source of magma. When such magma erupts to the surface, it creates a fine-grained rock that crystallizes quickly. This process is not to be confused with that creating Diorite rocks, which form when magma does not erupt, but instead cool and crystallize slowly. Quartz is among the most common elements to be found in Andesite.


In the modern world, much like Basalt, we use Andesite for many construction purposes, including aggregated gravel for roadbeds. We also see Andesite used in famous statues and monuments around the world. Many artifacts found in ancient temples and monuments, including the famous 'Head of Buddha' found in the Indonesian Mountains, are made from Andesite. This rock also has a resistance against slipping, which makes it an excellent choice for floor tiling work.


The famous saying “if it can’t be grown, it must be mined” applies to many rocks and minerals, and Andesite is no exception. Mines all over the world work to cultivate the rock and extract it from its natural deposits. Many commercially viable Andesite mines are found across Central America, Europe, and Southern Asia. Our Earth's natural surface is predominately Andesite, so the supply will likely never run out. Andesite has proven time and time again to be one of our most readily useful and plentiful natural resources.

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