Which term describes a metamorphic texture with minerals arranged in layers or bands?

Which term describes a metamorphic texture with minerals arranged in layers or bands?

• A. Foliation
• B. Cleavage
• C. Fracture
• D. Luster

Answer: (A)

Foliation is a metamorphic texture formed when minerals in a rock become aligned in parallel layers or bands due to directed pressure during metamorphism. This alignment causes a layered, banded appearance as platy or elongated minerals (like micas) rotate and stack along planes of pressure. That layered look is what defines foliation, and you can see it in rocks such as slate, phyllite, and schist, with increasing metamorphic grade showing more distinct banding. Cleavage, by contrast, describes how individual minerals tend to break along flat, smooth planes and is a mineral property rather than the rock’s texture. Fracture refers to how a rock or mineral breaks in irregular surfaces, not along planes. Luster is about how light reflects off a mineral’s surface, not about a layered texture.

Foliation is a metamorphic texture formed when minerals in a rock become aligned in parallel layers or bands due to directed pressure during metamorphism. This alignment causes a layered, banded appearance as platy or elongated minerals (like micas) rotate and stack along planes of pressure. That layered look is what defines foliation, and you can see it in rocks such as slate, phyllite, and schist, with increasing metamorphic grade showing more distinct banding.

Cleavage, by contrast, describes how individual minerals tend to break along flat, smooth planes and is a mineral property rather than the rock’s texture. Fracture refers to how a rock or mineral breaks in irregular surfaces, not along planes. Luster is about how light reflects off a mineral’s surface, not about a layered texture.