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Extrusive igneous rocks have small crystals.
Why do extrusive rocks have small crystals?
Extrusive rocks are formed as lava flows cool immediately after a volcano erupts. This fast cooling forces the crystals to develop in a short period of time. Hence, the individual mineral molecules only have enough time to align themselves in a small crystalline lattice. That is why an extrusive igneous rock has a very high density of tiny mineral crystals (an aphanitic texture).
Why do intrusive rocks have large crystals?
Intrusive rocks are formed beneath the earths surface where the temperature is high and magmatic intrusions cool over a very long period of time. Since they solidify so slowly the individual mineral molecules have much more time to arrange into very large crystals.
Do all igneous rocks have crystals?
Obsidian is an igneous rock that solidifies almost in an instant. This gives no time for any crystals to develop. This is why obsidian has a very smooth glass like texture.
Wiki User
∙ 13y ago
Wiki User
∙ 13y agoExtrusive igneous rocks do not form large crystals because they are cooling on or near Earth's surface. Which is not underground. As it is cooling ABOVE ground because of the weather up in the atmosphere is cooler Extrusive rocks cool sooner.
While INTRUSIVE rocks are cooling below, which is hot. and takes more time.
Wiki User
∙ 13y agoAn intrusive igneous rock cools from a molten state far underground. Consequently, it cools off much more slowly than does an extrusive volcanic rock. The much longer cooling time gives atoms and molecules longer to migrate through the liquid magma and assemble into crystals. To put it another way, the atoms and molecules aren't forced to crystalize in their immediate vicinity, but have more time to migrate farther through the fluid and join a crystal somewhere else, thus making that more distant crystal larger than it would be if those atoms had to join a nearby crystal.
Wiki User
∙ 12y agoExtrusive rocks cool quickly and there is not sufficient time for crystals to grow large. When rocks cool below the surface of the earth (intrusive rocks) the magma cools much slower allowing much larger crystals to grow.
Wiki User
∙ 14y agoMore time is spent in the solidification phase as the magma or lava cools, allowing crystals to grow larger.
Wiki User
∙ 11y agoExtrusive rocks cool quickly and therefore don't have time for the crystals to grow large
Wiki User
∙ 11y agoThe lava solidifies so quickly at or near the surface, that minerals have very little time to organize into their crystal structures.
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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.
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
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.
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.
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.
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
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.
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.
What type of crystal are formed from in extrusive igneous rocks?
Small crystals, invisible without magnification.
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 type of igneous rocks have individual mineral crystals that are too small to be seen without magnification?
Extrusive Igneous Rocks. Basalt (Plankey1995 JF)
What rock cools on the surface?
Lava cools quickly and forms rocks with small crystals. They are called extrusive igneous rocks.
What is the term given to igneous rocks with crystals too small to see without a hand lens?
These are extrusive igneous rocks with an aphanitic texture.
What is a black intrusive rock with small crystals?
Intrusive rock normally has visible crystals. Extrusive igneous rock has small crystals. A black extrusive igneous rock with small crystals could be basalt.
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.
What is the name of igneous rocks that have large crystals and small crystals?
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).
