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This question has a very complex answer and you would do best to look at a chart, in order to have a full grasp of the answer. There are several categories and subcategories, so the answer can vary, depending on the depth of the answer being sought and the setup of the chart you are using. Because of this fact, if you are learning this subject in school, and seeking to answer your teacher's / professor's question, then you might want to check your book for a chart first.

To answer your question though, the categories are as follows:

Phaneritic, which means it contains coarse grains / visible crystals. Within the phaneritic category, there is a subcategory which contains larger crystals, called pegmatitic, (but they are still phaneritic too).

Porphyritic, which means it contains a mixture of coarse and fine grains, to put it simply. (To put it less simply, it is fine-grained and contains appreciable phenocrysts.)

Aphanitic, which means it is fine-grained.

Glassy, which looks like glass. (Think of obsidian.)

Vesicular, which contains gas holes, made from gas bubbles. (Think of pumice.) But depending on the chart, this category may or may not fall under glassy, since pumice, for example is actually made of frothy glass. Futhermore, some types of vesicular rocks may be subdivided into a category called frothy.

Pyroclastic, which is made up of fragmented volcanic debris. (However, this category may be divided depending on fragment size. The subcategories are volcanic tuff, (which has fragments under 2 mm in size), and volcanic breccia, (which has fragments over 2 mm in size).

Again, the answers sought can depend on the depth of knowledge being sought. For example, if you are seeking this answer for a school assignment, your teacher or professor might only be seeking phaneritic, aphanitic, porphyritic, glassy, and pyroclastic. However, they may want to see the subcategories of pegmatitic, frothy, vesicular, volcanic tuff and volcanic breccia. The answers can be more in depth too, but I hope this is enough to help you. Again, I recommend looking at any handouts or your book, if you are a student, in order to ascertain just what depth of knowledge your teacher / professor expects you to have.

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Related Questions

How do Igneous rock with glassy textures?

An igneous rock with a glassy texture cooled from its' liquid state very quickly, an example of this would be obsidian, a volcanic glass.


A lava flow is an example of an igneous rock one of the two main igneous rock groups?

It is an example of extrusive igneous rock.


What are two different igneous rock textures?

*fine-grained *coarse-grained


When melted rock cools it forms?

When melted rock cools, it forms igneous rock. The process of cooling allows the molten rock, also known as magma or lava, to solidify and form crystals. Igneous rocks can have different textures and compositions depending on how quickly or slowly the rock cools.


What is the effect the cause is melted rock cools?

When melted rock cools, it solidifies into igneous rock. This process can result in the formation of crystals within the rock depending on the rate at which it cools. The cooling process can also lead to the creation of different textures and structures in the igneous rock.


Is it possible to have an igneous rock with no crystals?

yes


How do two igneous rocks have the same mineral composition but different textures?

The texture of an igneous rock refers to the size of its mineral crystals. If the common magma of both igneous rocks has experienced differences in cooling rates due to depth, they will have different textures. Slow cooling produces large crystals, and quick cooling produces small crystals. Granite and rhyolite are two igneous rocks sharing the same mineral composition, but having undergone different rates of magma cooling due to depth at solidification.


Are igneous rocks strong?

Igneous rocks have a wide range of strengths depending on factors like mineral composition and cooling history. Some igneous rocks, like granite, can be very strong and durable, while others, like pumice, can be quite weak and easily crumble.


Does igneous rock have to become sedimentary rock before it can become metamorphic rock?

No, igneous rock can undergo metamorphism without becoming sedimentary rock first. Metamorphism can occur in any rock type (igneous, sedimentary, or metamorphic) when exposed to high temperature and pressure, leading to the formation of new minerals and textures.


What is hardened lava called?

Hardened lava is called igneous rock. When lava cools and solidifies, it forms igneous rock through the process of crystallization. This rock can have different textures and compositions depending on the speed of cooling and the mineral content of the original lava. Examples of igneous rocks formed from lava include basalt, andesite, and rhyolite.


Rock that forms as a result of volcanic activity at or near the surface of the earth?

Extrusive igneous rock, such as basalt or rhyolite, forms from magma that cools and solidifies quickly on or near the Earth's surface. These rocks typically have fine-grained textures due to the rapid cooling process.


Rocks formed by the cooling and hardening of molten rock?

Igneous rocks are formed by the cooling and hardening of molten rock, either from volcanic activity or magma cooling below the Earth's surface. Examples include granite, basalt, and obsidian. These rocks can have coarse or fine textures depending on the rate of cooling.