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Obsidian is an extrusive rock and is formed from rapidly cooling magma.
Obsidian is also known as volcanic glass and one can find only sub-microscopic crystals in it. This is because it was cooled too fastly for large crystals to form. If the material that obsidian consists of were an intrusive rock and had a lot of time to cool down, one would find that it would be composed of easily visible crystals.
What else can I help you with?
What rock starts off as liquid?
Magma is molten rock found beneath the Earth's surface. It solidifies to form different types of igneous rocks like granite, basalt, and obsidian.
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.
Does obsidian cool quickly or slowly?
it cool quickly but i dont know know how. i have a science homework do tomarrow and i know it cools quickly, but another question is how do you know. i cant just right that i googled it!!!! HELP
What group of rocks does granite belong to?
Granite is classified as an intrusive igneous rock.
What rocks don't contain minerals?
most rocks from what i know contain minerals especially sedimentary rocks. and don't all rocks eventually become sedimentary rocks so really don't they all contain minerals to some extent :) hope it helped (by the way i am only a gcse student)
4 most commenly know igneous rocks?
Granite, Basalt, Gabbro, and Obsidian
How is an igneous rock created?
Igneous rocks are created when magma cools and solidifies either below the Earth's surface (intrusive igneous rocks) or on the surface as lava (extrusive igneous rocks). The rate of cooling affects the crystal size and texture of the rock, with slower cooling producing larger crystals. Examples of igneous rocks include granite, basalt, and obsidian.
During the rock cycle what forms when magma cools?
When magma cools you get intrusive igneous rock. Think of other ig words you know. Ignite, ignition they all mean heat. Igneous rocks are formed from rocks that have been heated so much they melt. When they cool they make new, igneous, rocks. If it's magma that cools that means it's still under the earth's crust so the igneous rock is intrusive. If it's lava that cools after flowing down a volcano it's an extrusive igneous rock that's formed.
What rock forms volcanic lava cools?
Extrusive igneous rock. To be more specific you have to know the composition of the lava. The most common type is basalt, but other types include andesite, dacite, and rhyolite.
What rock starts off as liquid?
Magma is molten rock found beneath the Earth's surface. It solidifies to form different types of igneous rocks like granite, basalt, and obsidian.
How do you know that obsidian rock cools quickly?
i dont know thats why i am asking you do you know
How do intrusive and extrusive rock different?
i dont know shut ap
How do extrusive and intrusive appear different?
i dont know shut ap
What igneous rocks are there in the wold?
i don't know where the wold is, but i can assume that they have a plethora of igneous rock.
How do intrusive and extrusive rock appear different?
i dont know shut ap
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 are the 6 igneous rocks?
i dont know what that is
