The type of rock texture that results when extreme pressure causes minerals in metamorphic rock to realign or separate out into dark and light bands is called foliation.

Here's a breakdown:

* Foliation: A planar (flat) arrangement of mineral grains within a metamorphic rock. This is often visible as stripes or bands of different colors or textures.

* Mineral Realignment: During metamorphism, intense pressure forces minerals to change their orientation. Minerals with similar chemical properties tend to group together, creating distinct bands.

* Dark and Light Bands: The dark bands are often rich in minerals like biotite (black mica) or hornblende (amphibole), while the lighter bands are more likely to be composed of quartz and feldspar.

Some common examples of foliated metamorphic rocks include:

* Schist: A medium-grade metamorphic rock with a distinct, platy foliation.

* Gneiss: A high-grade metamorphic rock with a coarser foliation and often exhibits distinct bands of light and dark minerals.

* Slate: A fine-grained metamorphic rock with a very fine-grained foliation, often exhibiting a shiny, smooth surface.

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