Kyanite schist 12

James St. John
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Kyanite schist 12
Kyanite schist 12

Metamorphic rocks result from intense alteration of any previously existing rocks by heat and/or pressure and/or chemical change. This can happen as a result of regional metamorphism (large-scale tectonic events, such as continental collision or subduction), burial metamorphism (super-deep burial), contact metamorphism (by the heat & chemicals from nearby magma or lava), hydrothermal metamorphism (by superheated groundwater), shear metamorphism (in or near a fault zone), or shock metamorphism (by an impact event). Other categories include thermal metamorphism, kinetic metamorphism, and nuclear metamorphism. Many metamorphic rocks have a foliated texture, but some are crystalline or glassy.

Schist is an intermediate- to high-grade, foliated metamorphic rock. It is highly variable in appearance, depending on the mineral content, which is a function of the precursor rock and specific temperature-pressure conditions. Garden-variety schists form by metamorphism of phyllites. Schists typically have medium- to large-sized crystals, unlike the microcrystalline nature of slate & phyllite.

Schist's foliated texture (= crystals aligned into bands or stripes or layers) is often only seen when specimens are viewed on edge.

Kyanite schist has prominent elongated, bluish-colored blades of kyanite crystals. Kyanite is an aluminum silicate mineral (Al2SiO5). It is usually encountered in some intermediate- to high-grade metamorphic rocks, but also occurs in some pegmatites (= very coarsely-crystalline, intrusive igneous rocks).

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Taken on: February 9, 2024
Tags: Everybody's photos tagged with kyanite kyanite Everybody's photos tagged with schist schist
Sets appears in:   • Schist    • Minerals - Silicates (Kyanite)   
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