Igneous rocks form from the cooling of molten rock or magma. There are two types of cooling that produce different igneous rocks: rapid cooling leads to volcanic rocks like obsidian near the surface, while slow cooling deep underground forms plutonic rocks like granite. Volcanic rocks include obsidian, lava, basalt, and pumice, which cool quickly above ground, whereas plutonic rocks such as granite, syenite, and pink granite form from slow cooling underground.
2. ● What are igneous rocks?
● What are the different types of cooling?
● Obsidian, volcanic lava, basalt, pumice
● What are plutonic rocks?
● Syenite, granite, pink granite
● Difference between volcanic rocks and plutonic rocks
● Webgraphie
● Authors
3. What are igneous rocks?
Igneous rocks are rocks that have been subjected to a very high temperature to
melt. So, when these rocks leave to the outside, depending on how it cools, leave
a type of rock or another.
4. What are the different types of cooling?
Rocks can be cooled by a slowly cooling or a quickly cooling method, so
depending on the cooling system, there can be rocks with large crystals or with
small crystals. An example:
❖With the quickly cooling: Obsidian
❖With the slowly cooling: Granite
6. Volcanic lava
VOLCANIC LAVA
Form: Different types of forms
Colour: Black / Gray
Fracture: Either way
Texture: Vitreous
Composition: Intrusive and extrusive
materials
Utility: Used in construction.
7. Basalt
BASALT
Form: Different types of forms
Colour: Gray, black.
Fracture: Straight
Texture:Usually they have a porphyritic
texture.
Composition: Pyroxene, calcic
plagioclase.
Utility: Mainly used in construction.
8. Pumice
PUMICE
Form: Differents types of forms
Colour: Yellow, Red, Light Grey
Fracture: Straight
Texture: Vitreous
Uses: For beauty items.
Composition: Feldspat, oligoclase,
albite, biotite, pyroxene.
9. What are plutonic rocks?
Plutonic rocks are those igneous rocks that have been
formed by slow cooling in depth and in large masses of
magma.
10. Granite
GRANITE
Colour: White, pink or gray
Form: Differents types of forms
Fracture: Failures
Texture: granular and phaneritic
Composition: 74.5% silicon, 14%
alumina, 9.5% of sodium and
potassium oxides (Na2O, K2O) and
2% other oxides
Utility:it Is used in construction
11. Syenite
SYENITE
Form: Differents types of forms
Colour:White, blak and pink
Fracture: Straight
Texture: Vitreous
Composition: It is composed of
orthoclase and plagioclase, with small
amounts of hornblende, mica, auguita
and magnetite.
Utility: Used in construction.
12. Pink Granite
PINK GRANITE
Colour: Pink
Form: Differents types of forms
Fracture: Thick
Texture: pimpled texture
Composition:Quartz, feldspar and mica
Utility: It used in construction
13. Difference between volcanic rocks and plutonic
rocks
The volcanic rocks are formed by the cooling of lava at the Earth’s surface or
under the sea.
The plutonic rocks are formed by slow cooling in depth and in large masses of
magma.
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