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Normally, extrusive igneous rocks exhibit an aphanitic texture. Examples would be basalt and rhyolite.
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Do phaneritic igneous rocks contain viewable crystals?
By definition, yes. In contrast, aphanitic rocks do not have visible crystals.
How do you classify igneous rocks from other types of rock?
Igneous rocks are identified by first looking at the color index. Felsic igneous rocks contain mostly potassium feldspar. Intermediate igneous rocks contain mostly plagioclase feldspar. Mafic igneous rocks contain pyroxene, olivine, and plagioclase feldspar. Ultra mafic igneous rocks contain mostly olivine. Then igneous rocks are identified based on texture. For example, the texture of igneous rocks can be aphanitic, pegmatitic, phaneritic, glassy, vesicular, etc.
What is the color of the igneous?
It can be almost any color from white to black to red depending on where it is from.
What igneous rock cooled the most rapidly?
Igneous rocks with very small or no visible crystals are formed by rapid cooling. A good example would be obsidian (which is a volcanic glass) and BAsalt which may have an aphanitic texture (crystals to small to see with the naked eye).
What are some examples of igneous rocks?
Igneous rocks are generally classified first on the basis of their formation (and therefore their texture) as intrusive or extrusive. Intrusive rocks are solidified from magma under the surface resulting in a visible crystalline texture, and extrusive igneous rocks are solidified from lava at or near the surface, resulting in a small or nearly invisible crystalline texture.Igneous rock can additionally be classified by general chemistry composition as felsic, intermediate, mafic, and ultramafic. Felsic rocks are higher in silica and aluminum. Maficrocks are higher in magnesium and iron.Examples of igneous rock include:pumicebasaltandesitewehrlitemonzoniteanorthositewelded tuffnepheline syeniteaplitewebsteritekimberlitegabbrodioritegranitebasanitetroctolitepegmatitediabasepicritelatitegranodioritetonaliteperidotiteignimbritehornblenditelampophyrephonolitedunitesyenitetachylytemonzogranitetephritegranophyreboniniterhyodacitetrachytecarbonatiteharzburgiteicelanditepyroxenitetrachyandesitefoidoliterhyoliteobsidianscoriaWords used to describe igneous rock or igneous rock typesinclude: ultramafic, mafic, intermediate, felsic, aphanitic, porphyritic, phaneritic, extrusive, intrusive, vesicular, glassy, coarse grained, fine grained, acidic, basic.
What is the term given to igneous rocks with crystals too small to see without a hand lens?
These are extrusive igneous rocks with an aphanitic texture.
Do phaneritic igneous rocks contain viewable crystals?
By definition, yes. In contrast, aphanitic rocks do not have visible crystals.
What igneous rock is aphanitic texture?
These are igneous rocks that are too fine textured to an extent that there mineral grains or crystalline texture cannot be seen or distinguished with the necked or unaided eyes. They appear or occur as a whole single massive crystalline extrusive body of Igneous origin. Example is Obsidian.
How do you classify igneous rocks from other types of rock?
Igneous rocks are identified by first looking at the color index. Felsic igneous rocks contain mostly potassium feldspar. Intermediate igneous rocks contain mostly plagioclase feldspar. Mafic igneous rocks contain pyroxene, olivine, and plagioclase feldspar. Ultra mafic igneous rocks contain mostly olivine. Then igneous rocks are identified based on texture. For example, the texture of igneous rocks can be aphanitic, pegmatitic, phaneritic, glassy, vesicular, etc.
How are basalt and granite different in their Orgin texture and mineral composition and how are they similar?
Both rocks are igneous rock but basalt is an aphanitic igneous rock while granite is a common type of felsic intrusive igneous rock.
If the lava cools quickly the crystal are what?
If lava cools quickly, the minerals don't have as much time to form crystals, so the crystals do not become very large. Igneous rocks that cooled quickly and have small crystals are described as "aphanitic" igneous rocks.
Which igneous rocks fine grained due to fast cooling?
When igneous rocks form by cooling quickly, their microstructure includes fine grains. It is the aphanitic igneous rock that includes andesite, basalt, and rhyolite. Wikipedia has more information, and a link is provided below. If you wish to wade on into the depths of rock microstructures, you can link on from there.
Small grained rocks have what texture?
Fine grained rocks are considered aphanitic.
Which igneous rock cools the fastest glassy aphanitc pegmatic and porphyritic?
Glassy igneous rocks cool the fastest. The most likely had more nucleation. Pegmatic cooled the slowest, which is why its crystals are larger than 1 cm. Phaneritic is the next slowest in cooling. Porphyritic has slow then rapid cooling, while aphanitic igneous rocks also have rapid cooling.
When molten rocks cools what rocks form?
igneous rocks
What is the color of the igneous?
It can be almost any color from white to black to red depending on where it is from.
What igneous rock cooled the most rapidly?
Igneous rocks with very small or no visible crystals are formed by rapid cooling. A good example would be obsidian (which is a volcanic glass) and BAsalt which may have an aphanitic texture (crystals to small to see with the naked eye).
