The three main types of rocks that make up the earth's crust

The Earth's crust is a nearly elliptical spherical body with a flat diameter of about 6300 km
.
The earth is divided into three parts of the crust, mantle and core by surface and interior, and their interfaces are 5 to 65 kilometers in different regions with different thicknesses of crustal depths, and the mantle is between the bottom surface of the earth's crust and a depth of about 2900 kilometers, from 2900 kilometers to the core
of the earth.
The Earth's crust is made up of three main types of rocks (often called stones), namely magmatic rocks, metamorphic rocks, and sedimentary rocks
.
Sedimentary rocks cover more than 60% of the surface area, and we see that the surface of many areas is soil or gravel, that is, the surface weathering shell formed by rock weathering, or newly deposited loose material
.

(l) magmatic rock: magmatic rock is a rock formed by magma condensation, magma is in a very deep underground, with huge pressure, under the tectonic movement of the earth's crust, it can seep along the crustal fissures to the upper layer of the earth's crust or directly erupt from the ground (volcanic eruption), due to the pressure drop, a large number of volatile substances in the magma escape, the temperature also gradually decreases, magma gradually condenses, crystallizes into magmatic rock
.

(2) Metamorphic rock: metamorphic rock is a new rock formed by metamorphosis of the original rock
under the action of external conditions (temperature, pressure, etc.
).
Common metamorphic rocks are Dali rock (which can be used as a decorative material) and quartzite
.

(3) Sedimentary rock: Sedimentary rock is the original host rock (magmatic rock, metamorphic rock and sedimentary rock) subjected to weathering and erosion, and the rock
is formed by handling, sedimentation and diagenesis.
Sedimentary rocks are the most important types of rocks
that make up the surface of the earth's crust.
It is rich in minerals, such as gold, silver, copper, iron, tin, etc.
Most of them are stored in sedimentary rocks, and oil is also generated in sedimentary rocks, and most of them are stored in
sedimentary rocks.