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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).
What else can I help you with?
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?
Igneous rocks can have both small and large crystals, depending on how quickly they cool. If an igneous rock cools slowly beneath the Earth's surface, it can form large crystals, while rapid cooling at the Earth's surface or in an eruption can result in small or no visible crystals.
What are Igneous rocks that have large crystals and small crystals?
Igneous rocks with large crystals are called intrusive rocks, formed from magma cooling slowly beneath the Earth's surface, allowing for large crystals to form. Igneous rocks with small crystals are called extrusive rocks, formed from lava cooling quickly on the Earth's surface, resulting in small crystals due to rapid cooling.
Where would you expect to find an igneous rock with small crystals?
You would expect to find an igneous rock with small crystals near the Earth's surface where the rock cools relatively quickly, such as in volcanic eruptions or magma intrusions that do not have much time to grow large crystals. These rocks are known as volcanic or extrusive igneous rocks.
Do igneous rocks have large crystals?
It depends on the cooling rate of the magma. If the magma cools slowly underground, large crystals can form, creating intrusive igneous rocks. If the magma cools rapidly on the Earth's surface, small crystals or glassy textures can result in extrusive igneous rocks.
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.
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.
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 type of crystal are formed from in extrusive igneous rocks?
Extrusive igneous rocks form fine-grained crystals due to rapid cooling at Earth's surface, resulting in minerals like basalt, andesite, and rhyolite. These rocks cool quickly, preventing the formation of large crystals typically found in intrusive igneous rocks.
Why is it that some igneous rock is made of large crystals and some is made of small crystals?
An igneous rock's crystal size is dependent on how long it takes to cool from magma into a solid. Intrusive igneous rocks, the ones that solidify from magma underground, are slow to harden, giving crystals plenty of time to grow larger. Extrusive igneous rocks, formed from lava above ground, cool fairly rapidly, not allowing the crystals much time to grow in size.
What igneous rock has crystals that are not visible?
Extrusive igneous rock consists of mineral crystals that are not observable with the naked eye. Obsidian is an extrusive igneous rock (volcanic glass) where there technically are no mineral crystals.
Some WHAT igneous rocks have individual mineral crystals that are too small to be seen without magnification?
Aphanitic igneous rocks have individual mineral crystals that are too small to be seen without magnification. These rocks cool rapidly, resulting in the formation of tiny crystals. Examples include basalt and rhyolite.
