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What metamorphic rock has high grade metamorphism and minerals are segregated into bands?


What kind of metamorphic rocks develop a layered striped appearance?

Foliated Metamorphic Rocks: Some kinds of metamorphic rocks — granite gneiss and biotite schist are two examples — are strongly banded or foliated. (Foliated means the parallel arrangement of certain mineral grains that gives the rock a striped appearance.)

What does crystal size tell us about the igneous rocks?

The size of crystals in an igneous rock is an important indicator of the conditions where the rock formed. An igneous rock with large crystals probably indicates that the rock formed deep within the Earth, since it is typically warmer deep inside the Earth than near the surface.

Why are crystals clearly visible in granite?

1: Granite is a classic coarse-grained (phaneritic) intrusive igneous rock. The slow cooling process allows crystals to grow large, giving the intrusive igneous rock a coarse-grained or phaneritic texture. The individual crystals in phaneritic texture are readily visible to the unaided eye.

Which factor is most important in controlling the crystal size of an igneous rock?

The texture of a rock refers to the size, shape and arrangement of the mineral grains in the rock that give the rock its overall appearance. The most important, but not only, factor that controls the grain size of a rock is its cooling history. Grain size tells us much about the crystallisation of an igneous rock.

What minerals are most common in granite?

The principal constituent of granite is feldspar. Both plagioclase feldspar and alkali feldspar are usually abundant in it, and their relative abundance has provided the basis for granite classifications. In most granite, the ratio of the dominant to the subdominant feldspar is less than two.

What determines the size of crystals in rocks?

The size of crystals in metamorphic rocks is determined by heat and pressure.

What affects the size of crystals?

The factor that affects the size of the crystals is the cooling rate of the molten rock or magma. If the magma cools rapidly, the crystal formed is very small, whereas if the magma cools slowly, the crystal formed is large.

Why do we obtain larger crystals if a solution of an organic compound is allowed to cool slowly?

Slow cooling of the saturated solution promotes formation of pure crystals because the molecules of the impurities that don’t fit too well have time to return to the solution. The solid impurities must be filtered using a gravity filtration process.

What are the most common coarse rocks?

Most Common Types of Igneous Rocks

  • Types. There are two kinds of igneous rocks.
  • Granite. Granite is a medium to coarse-grained igneous rock that is formed intrusively.
  • Basalt. Basalt is one of the most common types of igneous rocks in the world.
  • Gabbro. Crushed gabbro is commonly used as concrete aggregate, railroad ballast and road metal.
  • Pumice.