A lot vs. Alot: 9 Grammatical Pitfalls
Any of a series of dark silicate minerals having the general chemical formula ABSi2O6, where A is either calcium (Ca), sodium (Na), magnesium (Mg), or iron (Fe), and B is either magnesium, iron, chromium (Cr), manganese (Mn), or aluminum (Al). Pyroxenes vary in color from white to dark green or black and are characterized by a rectangular-shaped cross section. They can be either monoclinic or orthorhombic and occur in igneous and metamorphic rocks. The minerals enstatite, diopside, and augite are pyroxenes.