#structural rock layout

• Argillite — A compact argillaceous sedimentary rock, structurally formed through the diagenesis and deep cementation of clay muds, characterized by a higher hardness than simple clay and by the absence of fissility or the ability to split into thin sheets (unlike clay shales). In a geological sense, argillite represents an intermediate stage of metamorphism between soft pelitic sedimentary rocks and crystalline clay shales.