Phyllite

Type Metamorphic Rock
Texture Foliated; Fine-grained
Composition Muscovite, Biotite, Quartz, Plagioclase
Index Minerals
Color Shiny Gray
Miscellaneous Foliation surface has a satiny sheen and crinkled appearance
Metamorphic Type Regional
Metamorphic Grade Low Grade (Higher than Slate)
Parent Rock Shale or Mudstone
Metamorphic Environment Low grade regional metamorphism along a convergent plate boundary