Mafic Vs. Felsic - The Difference Between Mafic and Felsic

Felsic and mafic rocks are two main types of igneous rocks, which are rocks that are formed from the cooling and solidification of magma or lava. Felsic rocks are high in silica (SiO₂), while mafic rocks are low in silica. This difference in silica content gives the two types of rocks different physical and chemical properties.

Mafic Vs. Felsic Rocks: The Difference Between Mafic and Felsic

Felsic Rocks

Felsic rocks are typically light in color, such as white, pink, or gray. They are also relatively low in density and have high melting points. Felsic rocks are composed of minerals such as quartz, feldspar, and mica.

Mafic Rocks

Mafic rocks, on the other hand, are typically dark in color, such as black or green. They are also relatively dense and have low melting points. Mafic rocks are composed of minerals such as olivine, pyroxene, and amphibole.  

Formation of Felsic and Mafic Rocks

Felsic rocks are formed from the cooling and crystallization of felsic magma, which is relatively rich in the lighter elements silicon, oxygen, aluminum, sodium, and potassium. Felsic magma is less dense and more viscous than mafic magma, so it rises more slowly through the Earth's crust. When it reaches the surface, it can either cool and crystallize into extrusive felsic rocks like rhyolite and obsidian, or it can intrude into the surrounding rock and cool slowly to form intrusive felsic rocks like granite and pegmatite.

Mafic rocks are formed from the cooling and crystallization of mafic magma, which is relatively rich in the heavier elements magnesium and iron. Mafic magma is more dense and less viscous than felsic magma, so it rises more quickly through the Earth's crust. When it reaches the surface, it can either cool and crystallize into extrusive mafic rocks like basalt and scoria, or it can intrude into the surrounding rock and cool slowly to form intrusive mafic rocks like gabbro and dolerite.

Mineral Composition of Mafic and Felsic Rocks

Mafic rocks are dark in color and have a high density. They are typically composed of the following minerals: