Phyllite / RU Geology / by Grace Psenicska

Description

Phyllite is a foliated metamorphic rock that formed when fine-grained sedimentary rock such as shale or mudstone was buried and mildly altered by the heat and directed pressure of regional metamorphism. It is composed mainly of flake-shaped mica minerals in strong parallel alignment, which allows the rock to be easily split into sheets or slabs. It is primarily composed of quartz, sericite mica, and chlorite. # Phyllite's Physical Properties 1. Color: **gray, black, tan, brown** 2. Streak:**white** 3. Luster: **Phyllitic (Silvery, Nonmetallic)** 4. Cleavage/Fracture: **Phyllitic cleavage (Slaty, One flat or crinkled plane)** 5. Hardness: **1-2** 6. Specific Gravity: **2.72-2.73** 7. Texture: **Foliated; Fine-grained**