Phlogopite - KMg₃(Si₃Al)O₁₀(OH)₂

Habit: Brownish red, dark brown, yellowish brown, green or white. Crystals six-sided, thick tabular to prismatic, commonly tapered; also coarse-grained or platy. Pearly to submetallic luster; transparent to translucent. White streak.

Environment: Found in contact and regional metamorphic limestones and dolomites and ultramafic rocks.

Etymology: From the Greek phlogopos, meaning "resembling fire," in allusion to its red tint.