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It has cooled slowly under the Earth e.g. in magma chamber. This is why granite has large crystals but extruded/erupted lava only has microscopic crystals since the latter has cooled very quickly.
Wiki User
∙ 14y ago
Wiki User
∙ 7y agoThose that cool slowly, allowing crystal to grow from the hot magma. Gabbros and Granites. These are called intrusive rocks , which cool slowly beneath the earths surface, therefore allowing time for the formation of well structured and organised crystals. The opposite is an extrusive process, as rocks are spewed out for example from a volcano, gases quickly escape and as a result of the temperature difference of the surrounding environs and atmosphere these rocks cool quickly therefore they lack any substantial well developed crystals. E.g. obsidian, pumice, scoria and vesicular basalt.
Wiki User
∙ 14y agoIntrusive igneous rock has visible crystals due to the increased time spent in cooling from magma.
Wiki User
∙ 7y agoSlow cooling.
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When Magma is launched from a volcano forms what type of rock?
A volcano is made of extrusive igneous rock. The specific type of igneous rock will vary from one volcano to another.
What does grain-size tell you about the cooling history of a rock?
Slower rates of cooling will create larger crystals. Rapid cooling allows little time for element accumulation in the crystal, therefore, the crystals created will be smaller. Larger, visible crystals in igneous rock indicate that the magma was slow cooling, usually at depth. Much smaller crystals in igneous rock indicate rapid cooling of lava, usually at or near the surface. Crystals in igneous rock will grow larger and have more time to accumulate material for their growth the more time they have at their crystallization temperature.
What does igneous rock contain?
Randomly arranged interlocking crystals and no fossils :)
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 are two properties used to classify igneous rock?
Igneous rocks are usually classified by their chemical composition (acidic or basic), and by whether they formed underground (intrusive, characterised by large mineral crystals) or on the surface (extrusive, made of tiny, microscopic crystals). For instance, basalt is a basic, extrusive rock, and granite is an acidic, intrusive 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.
What igneous rock does not have large crystals?
sedimantry
What does crystal size mean?
In igneous rocks, large crystals mean that the rock cooled more slowly. Smaller crystals mean that the rock cooled more quickly.
What conditions lead to the formation of large crystals in an igneous rock?
Igneous rocks will develop large crystals is they cool slowly underground.
What conditions lead to formation of large crystals in an igneous rock?
Igneous rocks will develop large crystals is they cool slowly underground.
What is an extrusive igneous rock with large crystals?
granite
How can you tell that a rock is a igneous rock?
Well The Igneous Rock: When it Forms Underground the Pressure combines with Large crystals :)
What do small crystals in an igneous rock mean?
The size of the crystals in an igneous rock tells us how fast the magma cooled.
Are large crystals intrusive or extrusive igneous rock?
Intrusive
A type of instrusive igneous rock with large crystals?
Gabbro.
An igneous rock containing large crystals is most likely a?
intrusive rock
What do the large crystals in this igneous rock tell about the rock?
That it cooled very slowly.
