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directional fabric The alignment of linear elements, such as crystals, elongate xenoliths, or bedding— cleavage intersections in a rock. In igneous rocks, directional fabrics can be imposed by the flow of the silicate melt aligning phenocrysts or elongate xenoliths. In metamorphic rocks, directional fabrics can result from directional stresses acting on a rock during metamorphic recrystallization, resulting in the alignment of elongate metamorphic minerals such as hornblende. During folding, directional fabrics can result from the intersection of two planar surfaces such as bedding and cleavage to give an ‘intersection lineation’.