Geologists sometimes find it useful to classify igneous rocks based on color. Because color is sensitive to minor chemical differences it is not a very reliable index to the history or composition of any given rock; however, it has the merit of being...

Felsic is a term used in geology to refer to silicate minerals, magmas, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. The term combines the words "feldspar" and "silica." Felsic minerals...