Final answer:
The terms Mafic and Felsic are applied exclusively to igneous rocks, classifying them based on their mineral content such as ferromagnesian minerals in mafic rocks or silica-rich quartz in felsic rocks, influencing the rock's color and texture.
Step-by-step explanation:
The terms Mafic and Felsic apply ONLY to igneous rocks. Igneous rocks are classified based on their mineral content which influences their color and texture. Rocks with a high content of ferromagnesian minerals such as pyroxene, olivine, and amphibole are typically dark in color and are referred to as mafic rocks. These minerals are rich in magnesium ('ma') and iron ('f'), which explains the term 'mafic'. In contrast, igneous rocks that contain a larger amount of nonferromagnesian minerals like quartz, muscovite, potassium feldspar, and sometimes biotite and Na-rich plagioclase are light in color and are known as felsic or silicic rocks. The color differences in these rocks offer geologists a clue about the rock's mineralogy and can aid in their identification process.
Mafic rocks like basalt and gabbro are associated with the oceanic crust, while felsic rocks such as granite and rhyolite are typically found in the continental crust. Textural characteristics also aid in distinguishing between extrusive and intrusive igneous rocks, such as the fine-grained texture of rhyolite indicating an extrusive origin. Consequently, mafic and felsic are terms used to describe the composition and characteristics of an igneous rock based on the abundance of iron, magnesium, or silica, as well as light or dark mineral content.