fabric

In geology, "fabric" refers to the arrangement and orientation of the components within a rock, which influences its physical properties like porosity and permeability. This fabric can be primary, formed during sediment deposition, or secondary, resulting from deformation after deposition.1

In sedimentary rocks, fabric is determined by the orientation of grains, such as sand or clay minerals, and by how these grains are packed together. This packing affects the rock's density. In metamorphic rocks, fabric arises from mineral reactions and deformation, leading to a preferred orientation of crystals that is often not random. This preferred orientation is a key difference between metamorphic rocks and other rock types. The study of these fabrics helps geologists understand the forces that acted on rocks within the Earth's crust.12