Foliated Fine grain

You have now identified a fine grained, foliated metamorphic rock. To complete the identification process you must further classify the degree of foliation. Use the Table below to determine whether the rock you are identifying exhibits Slaty Rock Cleavage or phyllitic foliation; directions on how to name the metamorphic rock are in the last column.

Foliated Textures
Example
Name
Parent Rock
Slaty Rock Cleavage
  • very flat foliation that resembles mineral cleavage.
  • develops in clay or mica rich rocks-
  • indicative of low grade metamorphism

Slate

Modify the texture with a color description

Example Name: Red Slate

Mudstone or Shale

 
Phyllite
  • wavy wrinkled foliation made up of small platy minerals such as muscovite and chlorite.
  • usually gives rock a somewhat metallic look
  • indicative of an intermediate grade metamorphism
 Phyllite

Mudstone or Shale




©2006 Sean Tvelia