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Characterized by phyllitic foliation. Distinguished from slate by shiner, satinlike luster + more noticeable crystals (fine grain not very fine)

User Habax
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Phyllite is a type of foliated metamorphic rock that is distinguished from slate by its shiny, satin-like luster and more noticeable, yet fine-grained crystals. It indicates greater metamorphic change than slate, featuring visible grains and very thin layers of mica, describing a progression in the texture and composition of the rock.

Step-by-step explanation:

The subject of the question pertains to a type of metamorphic rock characterized by phyllitic foliation. Phyllite is distinguishable from slate by its shinier, satin-like luster and the presence of more noticeable, albeit still fine-grained crystals.

Unlike slate, which has smooth, flat surfaces due to slatey cleavage and very fine grains, phyllite has very, very thin, irregular layers of mica, usually showing a pale gray-green color and a satin sheen that covers the rock as a whole rather than individual flakes.

The uneven surfaces of phyllite and visible grains mark a progression from the dense, brittle characteristics of slate, as the rock undergoes increasing temperature and pressure during metamorphism.

Characteristics of Foliated Metamorphic Rocks

Foliated metamorphic rocks have a banded appearance due to the alignment of mineral crystals, where rocks such as slate, phyllite, and schist show a foliation texture without distinct color banding, differing from the layered gneissic foliation found in rocks such as gneiss.

Compared to non-foliated metamorphic rocks, which appear massive and structureless, foliated rocks like phyllite demonstrate a definite directional grain alignment and can split along parallel planes.

User Aanton
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