Metamorphic Rocks

Metamorphic rocks form as a result of the transformation of existing rock types, a process known as metamorphism, which means “form change.”

Metamorphic rocks are generally a modified form of Igneous, Sedimentary, or previous Metamorphic rock by various external weather conditions like temperature, pressure, volume, etc. and for such reason, the appearance, texture, and composition of rocks were changed from the previous characteristics.

Types of Metamorphic Rock

The types of metamorphic rock include the following-

1. Foliated metamorphic rocks- These are produced due to exposure to heat and pressure because of which they appear to be layered. Examples include Genesis and Phyllite.
2. Non-foliated metamorphic rocks- These rocks do not have layering and examples include marble and quartzite.

Metamorphic Rocks Properties

• These types of rocks are the hardest among the three types of rocks.
• These types of rocks do not contain fossils.
• These types of rocks are formed from all three types of rocks
• These rock types are generally found at the core of the various mountain ranges.

Metamorphic Rocks Examples

Since metamorphic rocks are formed from other rocks over large period of time, let’s look at each transformation example:

1. Sedimentary Rocks to Metamorphic Rocks:

• Slate from shale
• Marble from Limestone
• Marble from chalk and dolomite

2. Igneous Rocks to Metamorphic Rocks:

• Gneisses from granites
• Amphibolite from basalt
• Schist from Basalt

Based on the origin of rocks, they are classified into three types – Igneous rocks, Sedimentary rocks, and Metamorphic rocks. There are also a few rock substances of organic origin which sometimes contain fossils, for example, coal, peat, etc.

Rock Formation takes place by naturally occurring accumulation of mineral particles. The solid part of Earth is made up of various types of rocks differing from one another in texture, structure, permeability, mode of occurrence, and degree of resistance to denudation.