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What is an example of extrusive rock that has cooled too quickly for grains to form?
Wiki User
∙ 13y ago
Obsidian, which is volcanic glass, is a good example.
Wiki User
∙ 13y ago
Wiki User
∙ 12y agoObsidian
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How can you tell if a rock cooled fast or slow?
You would examine a fracture surface of the rock. Intrusive igneous rocks that have cooled very slowly underground have visible crystals and are said to have a phaneritic texture. Granite is an example of this type of rock. Extrusive igneous rocks that have cooled quickly from lava above or on the surface generally will have crystals too small to be visible with the naked eye, in a texture that is referred to as aphanitic. Obsidian is an example of this type of rock.
What type of rock that forms from magma or lava is rock?
Igneous rock is formed from the cooling of magma or lava.
What is the grain size of a fine grained igneous rock?
The individual grains (crystals) in quickly cooled magma are described as aphanitic--not visible without magnification.
What Evidence Would You Look For If Attempting To Classify A Piece of igneous Rock as Extrusive?
Extrusive igneous rocks have very small crystal grains.
What is the size of grains in pumice?
Pumice normally doesn't have any grains at all. It would be very unusual for it to have grains. Just like Obsidian, Pumice is cooled too fast to have any grains in it. One of the biggest differences between them is that Pumice is cooled with pockets of air while Obsidian has a glassy look.
What are fine grains of rocks?
Coarse is intrusive: the magma cooled slowly when it was formed causing big crystals... Fine is extrusive: the magma cooled quickly when it was formed causing small crystals!! your welcome mrs. bergs class:)
Is pumice a metamorphic rock?
No pumice is not a porphyritic igneous rock, a porphyritic rock is characterized by the presence of phenocrysts (large mineral grains) and very small mineral grains with none in between. This implies that there was two different stages of cooling. Pumice is an extrusive igneous rock that cooled very quickly.
How can you tell if a rock cooled fast or slow?
You would examine a fracture surface of the rock. Intrusive igneous rocks that have cooled very slowly underground have visible crystals and are said to have a phaneritic texture. Granite is an example of this type of rock. Extrusive igneous rocks that have cooled quickly from lava above or on the surface generally will have crystals too small to be visible with the naked eye, in a texture that is referred to as aphanitic. Obsidian is an example of this type of rock.
A rock that cools very quickly so that few or no mineral grains form is?
You can describe the rock by the process that allowed it to cool quickly: "Extrusive" or you can describe it by its texture: "aphanitic". An extrusive rock tends to be aphanitic = Rocks formed from lava flows tend to have small crystals.
What are some examples of rocks cooled quickly?
Two examples that come to my mind right away are Basalt and Obsidian. You can tell on your own if a rock has cooled quickly by whether or not you can see individual grains of minerals within the rock. So if you cant see any, then its most likely that the rock cooled quickly.
Why do extrusive rocks have small grains?
The intrusion is insulated by the surrounding rock, letting it cool very slowly and allowing crystals time to grow to larger sizes. In rapidly cooled rocks the grains can be so small that they are almost undetectable as no significant crystal growth happened.
Type of crystal grain that form when molten rock cools quickly?
Small crystal grains form when molten rock cools quickly. In an extrusive igneous rock, it's referred to as aphanitic texture.
What type of rock that forms from magma or lava is rock?
Igneous rock is formed from the cooling of magma or lava.
What is the grain size of a fine grained igneous rock?
The individual grains (crystals) in quickly cooled magma are described as aphanitic--not visible without magnification.
What Evidence Would You Look For If Attempting To Classify A Piece of igneous Rock as Extrusive?
Extrusive igneous rocks have very small crystal grains.
How does the rate of cooling influence crystal size of igneous rocks and how does that help you to distinguish between intrusive and extrusive igneous rocks?
The longer that magma is able to cool, the larger the crystals will be. Intrusive rocks will have larger crystals than extrusive rocks. For example granite (intrusive) has larger grains than rhyolite (extrusive).
Do extrusive igneous rocks have small grains since intrusive has large?
That is correct.
