Question

What are some differences between Igneous and Metamorphic rocks?

Answer 1

Igneous Rocks:-

1. Igneous rocks are formed when magma (or molten rocks) have cooled down and solidified.

2. Igneous rocks are commonly found inside the Earth’s crust or mantle.

3. The texture of igneous rocks depends on how fast it has cooled down. Textures range from coarse-grained to glassy.

4. They mainly have a crystal-like structure.

5. Igneous rocks are of two types – intrusive (solidified from magma below the earth’s surface) and extrusive (solidified from lava on the surface of the earth).

6. Examples:- Intrusive igneous rocks include – granite, diorite, pegmatite; Extrusive igneous rocks include – basalt, tuff, pumice, scoria, etc.

Metamorphic rocks:-

1. Metamorphic rocks are formed when other pre-existing rocks go through chemical and physical changes and form due to intense heat or pressure.

2. Metamorphic rocks are found on the Earth’s surface.

3. The texture of metamorphic rocks is foliated due to pressure. Some rocks may even appear to be non-foliated and banded.

4. They are very hard and may appear to be banded or layered.

5. Metamorphic rocks can be divided into two basic categories – foliated metamorphic rocks and non-foliated metamorphic rocks.

6. Examples:- Slate, marble, quartzite, phyllite, gneiss, hornfels, etc.

Answer 2

The main difference is that the Crystals in an igneous rock is shaped as it crystallized from a melt. The structure in a Metamorphic are earlier structures (Crystal, sedimentary fragments, etc ) that have been deformed or recrystallized due to heat or pressure or some chemical change.