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What is the name of igneous rocks that have large crystals and small crystals?
Wiki User
∙ 13y ago
Large Crystals = Intrusive
Small Crystals = Extrusive
The name relates to where the minerals were cooled (at at what rate). In the case of intrusive igneous, the rocks were formed above Earth's surface and were thus cooled quickly and the minerals had little time to become defined.
Extrusive rocks, therefore, were formed within the Earth's mantle and had a much longer time before being gathered to cool (as they slowly rose to the top).
Wiki User
∙ 13y ago
Wiki User
∙ 13y agoIntrusive igneous rocks have a larger crystal size then extrusive igneous rocks, because they cool slower, and thus have more time to form crystals.
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Why do some igneous rocks have larger crystals but other igneous rocks have crystals so small they have to be seen with a microscope?
Crystal size in igneous rock is dependent on the amount of time spent in cooling from magma or lava. More time means larger crystals. Rocks that have small crystals cooled quickly, so the minerals didn't have time to rearrange and form large crystals before the rock solidified. These small-crystalled rocks are described as aphanitic. Other rocks cooled slowly, so the minerals had time to rearrange and form large crystals before solidifying. These rocks are considered phaneritic. Some rocks cool slowly for a while, and then experience rapid cooling (such as magma that cools slowly inside a volcano, and then cools rapidly when the volcano erupts). Such rocks have large crystals surrounded by tiny crystals. Rocks that form this way are described as porphyritic.
Do extrusive igneous rocks have small grains since intrusive has large?
That is correct.
Do extrusive rocks cool quickly?
Extrusive rocks do cool quickly because either the crystals in the rock are very small or there are no crystals at all.
Does pumice have large or small crystals?
Pumice does not have crystals. It is made of glass.
What are 2 basic classifications of Igneous rock?
The two types of igneous rock are are intrusive and extrusive, depending on where they form. Intrusive igneous rock forms underground from slow cooling magma. Extrusive igneous rock forms at or near the surface from quick cooling lava.
Do igneous rocks have small crystals large crystals or no crystals?
It depends on the type of igneous rock. Intrusive igneous rocks such as granite have large crystals, extrusive igneous rocks may have small crystals as in basalt or no crystals as in pumice.
What are Igneous rocks that have large crystals and small crystals?
Such rocks are called porphyritic.
Where would you expect to find an igneous rock with small crystals?
you would find igneous rocks with small crystals at the bottom of the volcano, this is because when the rocks crack. It brakes apart into igneous rocks
Do igneous rocks have large crystals?
Yes, they can. Extrusive igneous rocks, which form outside the Earth's surface, often contain small or no crystals, because they cool quickly and the particles in the lava do not have much time to arrange themselves. Intrusive rocks, which form inside the Earth, generally have large crystals because they cool slowly. Granite is an example of an igneous rock with large crystals.
If the lava cools quickly the crystal are what?
If lava cools quickly, the minerals don't have as much time to form crystals, so the crystals do not become very large. Igneous rocks that cooled quickly and have small crystals are described as "aphanitic" igneous rocks.
Why do some igneous rocks have big crystals or grains and some igneous rocks have small crystals or grains?
how long they stayed in the volcano; how much time the crystals had to form
Do you think extrusive or intrusive igneous rocks are likely to have larger crystals?
If a rock has large crystals, it is an intrusive rock. Intrusive rocks form underneath the Earth's surface. Magma cools slowly so it has time to form large crystals. An example is granite, where you can see the crystals with your naked eye. Rocks that have small crystals are extrusive rocks. Extrusive rocks are ones that form from lava (blasted out of a volcano) so they cool very quickly, not allowing large crystals to form. An example is obsidian, where you cannot visibly see the small crystals; it just looks like one black, glassy rock.
Why do some igneous rocks have larger crystals but other igneous rocks have crystals so small they have to be seen with a microscope?
Crystal size in igneous rock is dependent on the amount of time spent in cooling from magma or lava. More time means larger crystals. Rocks that have small crystals cooled quickly, so the minerals didn't have time to rearrange and form large crystals before the rock solidified. These small-crystalled rocks are described as aphanitic. Other rocks cooled slowly, so the minerals had time to rearrange and form large crystals before solidifying. These rocks are considered phaneritic. Some rocks cool slowly for a while, and then experience rapid cooling (such as magma that cools slowly inside a volcano, and then cools rapidly when the volcano erupts). Such rocks have large crystals surrounded by tiny crystals. Rocks that form this way are described as porphyritic.
What is the difference in appearance between igneous rocks that have cooled slowly and igneous rocks that have cooled quickly?
Igneous rocks that cooled slowly are intrusive. Igneous rocks that cooled quickly are extrusive. Intrusive rocks form larger crystals, because the crystals have a longer time to grow. Extrusive rocks have small to no crystals, because they had little or no time to grow/form.
Some WHAT igneous rocks have individual mineral crystals that are too small to be seen without magnification?
Some extrusive igneous rocks have individual mineral crystals that are too small to be seen without magnification.
What feature in igneous rocks is the best indication of how rapidly the magma crystallized?
The size of the crystals. Large crystals mean the magma cooled slowly, small crystals are a sign that the magma was cooled quickly.
What is an igneous rock with small crystals?
If you're not looking for anything specific, any extrusive igneous rock will have smaller crystals, if any at all. This is because they cool quickly on the surface, leaving little time for crystals to form/grow.
