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Why do some igneous rocks have larger crystals but other igneous rocks have crystals so small they have to be seen with a microscope?
Wiki User
∙ 14y ago
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.
Wiki User
∙ 14y ago
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What are other kinds of rocks?
other kinds of rocks are sedimentary rock or igneous rock
Do you need to have a seed crystal to make other crystals?
No you can make some crystals with table salt by making a saturated solution look how to do it on line
What are the three types of rock and their formation?
there are 4 bill bob and jerry and the one in abi's head she likes to call a brain Igneous, Sedimentary, and Metamorphic.
Describe how an igneous rock may become transformed into other rock types and back into igneous rock?
Describe how an igneous rock may become transformed into other rock types and back into igneous rock? The Igneous Rock would have to go through many stages known as the Rock Cycle. The Rock Cycle steps would be: Igneous Rock than it would have to go threw erosion to become a Sedimentary Rock than it would have to go through Heat and Pressure to become a Metamorphic Rock. Then The Metamorphic Rock would have to go through melting to become a Molten Rock (Lave/Magma). Then finally it would have to go through cooling to become a Igneous Rock again<3[: ---♥PandaBabby69♥
How is a metamphic rock formed?
Formed by Sedimentary and Igneous rock,and even other types of Metamphic rock.
Why is there no quartz formed in magma after it has cooled?
If you can't see its crystals without a microscope it's because the rock solidified too rapidly for visible crystals to form. Whether or not quartz is found in cooled magma/lava is basically a product of the chemical makeup of the molten rock. Quartz is the predominate silicate mineral in felsic igneous rocks, but may be non-existent in mafic igneous rocks. If you are referring to the fact that most felsic igneous rocks containing quartz do not exhibit well formed quartz crystals, it is because quartz is one of the last minerals to crystallize from magma, and solidifies in the voids between other minerals that have already crystallized.
What type of rock is a crystal rock?
Virtually all rock contains mineral crystals of various sizes. Most volcanic rocks such as granite contain crystals of quartz and other minerals. Crystal size varies depending on the speed of cooling.
Describe how the cooling rate of magma affects the texture of igneous rock.?
The faster the rate of cooling the smoother the rock will be. The slower the rate the more rough the texture. The faster it cools the finer the texture of the rock. Slower cooling magmas tend to form courser grained igneous rocks. The more time a magma has too cool, the larger the crystals will be If all the minerals in the magma cools at about the same rate you will have roughly equal sized grains in the rock, in which case the rock will be of phaneritic texture. However you will have conditions in which some of the minerals will solidify while other minerals remain liquid, meaning those that have more time to solidify will have larger crystals . The minerals that solidify will have more time to grow as crystals while the other minerals in that magma will have less time and space to grow as crystals meaning those minerals will have smaller crystals. These rocks with crystals of various sizes are called porphoritic rocks (or porphory)
What kind of igneous rock texture results from slow cooling magma?
A coarse grained texture, referred to as a phaneritic texture, will be the resultant igneous rock texture. The slower the magma cools the more time minerals have to crystallize and thus grow bigger.
What kind of rock forms when magma intrudes into other rocks?
Intrusive igneous rocks. These have large crystals because it is warmer underground, therefore it has more time to cool, therefore the crystals have more time to form and grow, thus large crystals.
How are the textures of extrusive and intrusive igneous rocks different?
Extrusive igneous rocks have come to the surface when cooling down. Intrusive igneous rocks stay within the earth. This difference is important. When a magma comes to the surface, it's called a lava. On the surface, the lava will be subject to cooling by wind and water. This will happen fast. When a magma stays inside the earth, it will cool down considerably slower, because it has to radiate it's heat to the rest of the earth. This doesn't go fast because while water and air can flow, rock can't. The texture of an igneous rock has everything to do with the cooling speed. As a magma or a lava cools, it forms crystals. When the cooling happens relatively fast, these crystals do not have a lot of time to grow together, so you will get a lot of small crystals. When the cooling is very slow, the crystals will have more time to grow, and the crystal size will be a lot bigger. Take for instance granite. If you've ever seen it, you know you can see the crystals with the naked eye, because they are very large. Basalt, on the other hand has a very fine structure, you can't see the crystals without magnifying equipment like a microscope. So there you have it: an extrusive igneous rock will have a very fine texture, with small crystal sizes, an intrusive igneous rock will have a very coarse texture, with large crystal sizes.
What is the rate of cooling in reference to magma and lava?
The rate of cooling is the speed at which magma or lava crystallizes. When the speed is slow it results in big crystals. When the speed is fast it results in small crystals.
Why do andesite and diorite have large crystals?
The reason why all rocks may have large crystals are because of one of the following reasons: If the rock is an igneous rock: Igneous rocks form when magma/lava cools. The slower it cools, the larger the crystals because they have more time to develop. If the rock is a metamorphic rock: Metamorphic rocks form from heat and pressure on top of other rocks. The more heat and pressure that builds on top of it, the more likely it will have larger crystals. If the rock is sedimentary rock: Sedimentary rock forms when other rocks get eroded, deposited, compacted, and then cemented together. Usually if the rock takes longer in cementation, it'll have larger crystals. So basically the longer it has to form, the larger the crystals will get.
Is it extrusive rock that can have smooth texture because it is formed from lava that cooled so quickly that large crystals did not have time to form or is it intrusive?
Extrusive Igneous rock cools quickly above ground so it has a smooth texture so there isn't enough time for crystals to form and intrusive igneous rock forms inside a volcano or other underground hot place and takes longer to cool so crystals can form. It is extrusive.
What is the difference between intrusive and igneous rocks?
The difference between an Extrusive and Intrusive igneous rock is the way in which they cool. An Extrusive igneous rock cools very fast on the surface and is created by lava. Since the cooling process is very fast extrusive igneous rocks have very small crystals (fine grained). On the other hand an Intrusive igneous rock cools very slowly beneath the surface and is created by magma. Since the cooling process is very slow intrusive igneous rocks have very large crystals (coarse grained). In some instances there is also a third type of igneous rock. Technically it is an extrusive rock, but it resembles glass. This glass type of igneous rock forms when magma/lava is instantly cooled.
Comparision between metallurgical and biological microscope?
A metallurgical microscope is used to view opaque items and measure thin film, electroplating coatings, inclusions, grain size, and surface defects. A biological microscope, on the other hand, is used to view crystals, computer chips, cells, and tissues. It is also known as a high power compound microscope.
How does the crystal sizes of igneous rocks indicate the rate of cooling and whether the rock is extrusive or intrusive?
Generally, large crystals represent slow cooling rates and small crystals represent fast cooling rates. Crystals need time to form and since extrusive rocks cool very quickly, they have very tiny crystals and some don't even have crystals because the rate of cooling was so fast that crystals didn't have time to nucleate. On the other hand, intrusive rocks cool rather slowly allowing crystals to grow.
