When the structures are developed throughout the rock, planar or linear and in nearly equal quantity everywhere, then they are said to be penetrative such as a schistosity or slaty cleavage. Sometimes the term can be used when they are sufficiently well developed on a given scale only such as micro- or mesoscopic. If these elements are developed only in discrete zones and not throughout, then they are called nonpenetrative,

When the fabric is developed throughout the rock, planar in habit and in nearly equal quantity everywhere, then it is said to be penetrative such as a schistosity or slaty cleavage. Sometimes the term can be used when the fabric is sufficiently well developed on a given scale only such as micro- or mesoscopic. If these planar elements are developed only in discrete zones and not throughout, then they are called nonpenetrative,