👉 The term "phlogopite" is a mineralogy term that refers to the formation of phlogopite, a type of quartz crystal. Phlogopite is composed primarily of pyroxene (or pyrope) and feldspar, which are both minerals found in the Earth's crust. The crystals themselves are typically very small and irregular, resembling a single, black-sized cell with a slightly rounded edge. The term "phlogopite" was first used by Charles
