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Andesite has small crystals because it formed from lava that cooled relatively quickly at the Earth's surface, preventing larger crystals from growing. Rapid cooling does not allow enough time for the minerals to crystallize fully, resulting in smaller crystal sizes.
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Are large crystals found in diorite?
Large crystals can be found in diorite, typically consisting of plagioclase feldspar and amphibole minerals. These crystals are formed from the slow cooling of magma deep within the Earth's crust, allowing for the growth of larger mineral grains.
A matrix of fine crystals surrounding phenocrysts?
The matrix consists of small crystals formed from the same magma as the larger phenocrysts, but cooled more quickly. The phenocrysts are larger crystals that grew more slowly within the magma before the rock solidified. This type of texture is commonly found in volcanic rocks like rhyolite and andesite.
Compare the mineral composition of diorite with the mineral composition of andesite?
Both andesite and diorite are igneous rocks with an intermediate color index. Diorite; however, is intrusive and phaneritic, whereas andesite is aphanitic and extrusive. Andesite is said to be the extrusive equivalent of diorite. Diorite is made up of plagioclase feldspar and ferromagnesian mineral crystals, mainly amphibole. Contrarily, andesite may resemble rhyolite, meaning it presents a need for microscopic examination to see its mineral crystals. The two have a composition of plagioclase feldspar and amphibole, but it is much more difficult to detect in andesite.
What is andesite?
Andesite is a type of igneous rock that is typically light to dark gray in color. It forms when magma from the Earth's mantle solidifies and cools relatively quickly. Andesite is commonly found in volcanic regions such as the Andes Mountains in South America.
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.
Why do andesite have small crystals?
Andesite is an Igneous Rock. It has small crystals because it cooled quickly d;D
Is andesite phaneritic or aphanitic?
Andesite can be either phaneritic or aphanitic depending on how it formed. Phaneritic andesite has larger crystals that are visible to the naked eye, suggesting slower cooling and crystallization deep within the Earth's crust. Aphanitic andesite has smaller crystals that are only visible under a microscope, indicating faster cooling at or near the Earth's surface.
Are large crystals found in diorite?
Large crystals can be found in diorite, typically consisting of plagioclase feldspar and amphibole minerals. These crystals are formed from the slow cooling of magma deep within the Earth's crust, allowing for the growth of larger mineral grains.
Is andesite intusive?
Andesite is a type of igneous rock that can form both intrusively (inside the Earth's crust) and extrusively (on the Earth's surface). When andesite forms intrusively, it typically cools slowly and can create large crystals.
A matrix of fine crystals surrounding phenocrysts?
The matrix consists of small crystals formed from the same magma as the larger phenocrysts, but cooled more quickly. The phenocrysts are larger crystals that grew more slowly within the magma before the rock solidified. This type of texture is commonly found in volcanic rocks like rhyolite and andesite.
Compare the mineral composition of diorite with the mineral composition of andesite?
Both andesite and diorite are igneous rocks with an intermediate color index. Diorite; however, is intrusive and phaneritic, whereas andesite is aphanitic and extrusive. Andesite is said to be the extrusive equivalent of diorite. Diorite is made up of plagioclase feldspar and ferromagnesian mineral crystals, mainly amphibole. Contrarily, andesite may resemble rhyolite, meaning it presents a need for microscopic examination to see its mineral crystals. The two have a composition of plagioclase feldspar and amphibole, but it is much more difficult to detect in andesite.
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.
What is Andesite texture?
Andesite texture refers to the fine-grained, intermediate volcanic rock composed mainly of plagioclase feldspar and amphibole minerals. It typically exhibits a porphyritic texture, with larger crystals (phenocrysts) embedded in a matrix of smaller crystals (groundmass). This texture is formed by the slow cooling of magma beneath the Earth's surface.
Why does igneous rock have bigger crystals and some have small crystals?
The reason why is because of where it comes from in a volcano and how fast it cools. If it cools slowly then it will have bigger crystals because the longer it has to cool the longer the crystals have to grow. So dose that answer your question
What is andesite?
Andesite is a type of igneous rock that is typically light to dark gray in color. It forms when magma from the Earth's mantle solidifies and cools relatively quickly. Andesite is commonly found in volcanic regions such as the Andes Mountains in South America.
Why do you think that quick cooling makes small crystals form?
I think (and know) it is because there is less time for crystals to grow.
Are andesite grains small?
Andesite typically has a groundmass ~ 50% of grains <.25mm of metallic oxides and quartz interspersed with larger phenocrysts of pyroxene and plagioclase feldspar. Other accesory minerals may be present.
