What is another name for the extrusive rock?
volcanic rocks
What are the classification of igneous rock?
As has already been described, igneous rocks are classified into four categories, based on either their chemistry or their mineral composition: felsic, intermediate, mafic, and ultramafic.
What are some examples of an igneous rock?
These rocks include: andesite, basalt, dacite, obsidian, pumice, rhyolite, scoria, and tuff. Pictures and brief descriptions of some common igneous rock types are shown on this page.
What are the similarities of intrusive and extrusive rocks?
Intrusive and extrusive igneous rocks are alike in that they are both formed from the cooling and crystallization of molten substance (magma and lava,…
What is extrusive and intrusive rocks?
Devils Tower Rock. The two main categories of igneous rocks are extrusive and intrusive. Extrusive rocks are formed on the surface of the Earth from lava, which is magma that has emerged from underground. Intrusive rocks are formed from magma that cools and solidifies within the crust of the planet.
What do intrusive and extrusive igneous rocks have in common?
Intrusive igneous rocks cool from magma slowly because they are buried beneath the surface, so they have large crystals. Extrusive igneous rocks cool from lava rapidly because they form at the surface, so they have small crystals.
Which characteristics best identify differences between intrusive and extrusive rocks?
Crystal Size and Texture The most obvious difference between extrusive rocks and intrusive rocks is crystal size. Because extrusive rocks cool quickly, they only have time to form very small crystals such as basalt or none at all. On the other hand, intrusive rocks grow larger crystals because they take longer to cool.
Which feature is used to classify a rock based on its composition?
Rocks are classified mostly by its texture and its composition. When a rock is classified based on its composition the feature that is most used is the type of mineral in the rock. For instance, igneous rocks are made of silicate minerals, while quartz, K-feldspar, and muscovite are found in sedimentary rocks.