Intrusive rocks are formed when magma cools and solidifies below the earth’s surface, while extrusive rocks are formed when magma cools and solidifies above the earth’s surface
Intrusive rocks
Intrusive rocks are those that form from magma that cools and solidifies below the surface. Intrusive rocks are generally harder and more resistant to weathering than extrusive rocks.
Examples of intrusive rocks are diabase, diorite, gabbro, granite, pegmatite, and peridotite. intrusive rocks also called plutonic rocks
Granite is the most common intrusive rock on the continents; gabbro is the most common intrusive rock in the oceanic crust.
Extrusive rocks
Extrusive rocks are those that form from lava or magma that has cooled and solidified on the surface of the earth. These rocks are typically found in volcanic regions.
Some extrusive igneous rocks cool so fast that crystals do not develop at all. These rocks turn into glass. examples of this are rocks such as obsidian. other rocks such as pumice, contain holes where gas bubbles were trapped in the lava. These holes make pumice so light that they literally float in water. The most common extrusive rock is basalt. It is the rock that makes up the ocean floor
The difference between the two
Intrusive rocks are those that form from magma that cools and solidifies below the surface. Extrusive rocks, on the other hand, are those that form from lava that cools and solidifies above the surface. The main difference between the two is their mode of formation.
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