Foliated Textures

Foliated textures result from a parallel arrangement of flat, platy minerals such as muscovite. This is usually a result of mineral recrystallization in the presence of a directed pressure. Under this condition, the mineral grains will grow in an orientation that best distributes the force of the pressure. Typically, mineral grains will grow perpendicular to the force being enacted on them.

Rember texture is not only a description of mineral arrangement but also mineral size. The larger the crystal size within the metamorphic rock the greater the metamorphic grade. In other words metamorphic rocks with a coarse grained foliated texture have undergone a greater intensity of pressure. This information is useful in determining the conditions under which the rock has formed, which can give valuable insight into the geologic past.

To continue identifying your metamorphic rock select the appropriate grain size from the menu on the left