Non-Foliated Metamorphic Rocks Lack a Sheet-Like Structure.

Unlike other types of metamorphic rocks, non-foliated metamorphic rocks do not have a plate-like or sheet-like structure. Some non-foliated metamorphic rocks lack this structure because they are made of minerals that are not flat or uniform, so no matter how much pressure is applied, the grains will not align. Limestone is one common example of this type of rock.