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Why do some igneous rocks have larger crystals than others?
Leximillergp4115
The size of the crystals depend on the time it took the rock to cool. Slow cooling rocks have larger crystals because they had a longer time to grow their crystals. For example Basalt is an volcanic extrusive igneous rock that forms from rapid cooling of the magma and are usually located near the surface or on the ocean floor, it has finer crystals not visible by the naked eye. Granite is an intrusive igneous rock that forms from slow cooling of the magma within the earth crust, it has larger crystals.
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∙ 8y ago
Marcel Wolf
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Why do intrusive igneous rocks have shiny appearances?
Intrusive igneous rocks have a shiny appearance because they form slowly, giving them larger crystals.
What is a type of igneous rock that forms visible crystals?
Granite, gabbro, and diorite are a few igneous rocks that forms crystals. Igneous rocks that form visible crystals are intrusive igneous rocks, rocks that form under the earth's surface.
Do rocks that cool slowly from magma contain more crystals?
No. They would contain fewer, but larger mineral crystals when compared to igneous rocks which have cooled quickly from lava or magma.
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
Is gabbro an intrusive or extrusive igneous rock how do you know?
Intrusive, or plutonic, based upon the size of the crystals. Intrusive igneous rocks tend to have larger and more developed crystals than volcanic igneous rocks because of minimal exposure to air, causing the magma to cool more slowly.
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.
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.
Why do intrusive igneous rocks have shiny appearances?
Intrusive igneous rocks have a shiny appearance because they form slowly, giving them larger crystals.
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).
How is the size of mineral crystals in igneous rock related to the rate at which they cool?
When igneous rocks cool quickly, they have small crystals and have a texture that may be described as aphanitic. When igneous rocks cool slowly, they have much larger crystals and have a texture that may be described as phaneritic or pegmatitic.
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.
Rocks that have crystals?
Igneous rocks
What is a type of igneous rock that forms visible crystals?
Granite, gabbro, and diorite are a few igneous rocks that forms crystals. Igneous rocks that form visible crystals are intrusive igneous rocks, rocks that form under the earth's surface.
Why is a igneous rock appear smooth and glassy?
Some igneous rocks are very smooth and glassy (obsidian) while others have a very rough texture, such as the rocks used on the bottom of a propane gas grill. They are all formed from lava, but the glassy rocks cooled so fast that crystals did not have a chance to form. The rougher rocks cooled more slowly, allowing larger crystals to form--Slower cooling = larger crystals = rougher texture.
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 are Igneous rocks that have large crystals and small crystals?
Such rocks are called porphyritic.
Do rocks that cool slowly from magma contain more crystals?
No. They would contain fewer, but larger mineral crystals when compared to igneous rocks which have cooled quickly from lava or magma.
