What are the most common igneous rocks, and where do they generally occur?
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Granite, forms deep underground\nObsidian, the really dark and smooth black rock\nBasalt, which forms from volcanoes mostly\nPumice, the really light rock that floats on water\n\nand a few others, listed in the source site
673500
Igneous rocks in which the molecular proportion of aluminum oxide is less than that of sodium and potassium oxides combined
58331
Igneous rocks are formed with heat. They are most commonly found around volcanoes. Metamorphic rocks are formed with heat and pressure. Sedimentary rocks, like sandstone and limestone, are formed by pressure.
1069472
First of all any rock can undergo ductile formation under the right conditions...\n\n1.) Heat & pressure - if enough heat & pressure are applied as in conditions deep w/in the earth then ductile deformation can occur.\n\n2.) Time - if a rock has pressure applied over long periods of time then ductile deformation can occur. If done over short periods of time a rock may undergo brittle deformation no matter what type of rock it is.\n\nThe question you are asking I believe has to do w/ composition...\n\n3.) Composition - rocks w/ strong internal bonds are more likely to undergo brittle deformation whereas rocks w/ weak bonds will more than likely undergo ductile deformation. Rocks in the former category include igneous such as basalt & granite. Rocks in the latter category would include sedimentary & some types of metamorphic rocks.\n\nRocks such as quartz & feldspars tend to be very brittle whereas ones containing calcite & micas are more ductile.\n\nBased on this, the answer to your question would be dolomite just as the first person said.\n\nWhy? Rhyolite is composed of quartz & feldspar; Chert is made of cryptocrystalline quartz; Quartzite is made up of quartz (SiO2).\n\nDolomite is calcium magnesium carbonate or quite simply put, a carbonate rock. It will be more likely to deform than the other 3.
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The crust and mantle are generally solid.  The inner and outer core are molten rock and metal...very dense, but still liquid.
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The term comes from the Latin word "Ignis" which means fire. Igneous rocks are produced by melting within the earth and later cooling of the molten magma.\n\nThere are two major subdivisions of igneous rocks:\nExtrusive\nIntrusive\n\nExtrusive igneous rocks come from volcanic activity. They are "extruded' by being ejected from a volcano or being part of a slow moving lava flow on the surface of the earth.  Examples: basalt flows, pumice, obsidian, ash, scoria\n\nIntrusive igneous rocks are formed by these molten rocks as they cool within the earth. The slow cooling allows the rock to separate into different minerals and form grains. Large masses of intrusive rocks that harden within the earth are called batholiths and plutons, depending on the size.  Examples of intrusive igneous rocks are granite, gabbro, and monzonite. \n\nHere is a list with photos of examples:\nhttp://csmres.jmu.edu/geollab/Fichter/IgnRx/IgAlphabetical.html
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There are three basic types of rocks: igneous, sedimentary, and metamorphic.\n\nIgneous rocks are formed from molten magma or lava. Igneous rocks vary greatly in grain structure and size, depending upon how quickly the magma or lava cooled. An example of an igneous rock is obsidian.\n\nSedimentary rocks are formed when layers of sediment are compacted by pressure. They are often composed of fragments of materials derived from other rocks and minerals, especially quartz.\n\nMetamorphic rocks occur when igneous, sedimentary, or previously-formed metamorphic rocks are submitted to extreme heat or pressure beneath the earth's surface, changing their structure and appearance. They often exhibit "foliation" or color banding when mineral crystals are elongated due to pressure. An example of a metamorphic rock is slate.
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Nickel is a common trace element in rock. Nickel ores are comparatively rare on the earth crust. Most of our planet's nickel is believed to rest in the core, which is supposed to be a nickel-iron alloy similar to comets.
418501
Pumice, obsidian, and basalt are all extrusive igneous rocks.so yea basalt is extrusive
1119893
No it is not. Oceanic crust is composed primarily of basalt. Basalt is an extrusive igneous rock that cools quickly. Other types of rock commonly found on or beneath the unconsolidated sediments on the ocean floor are sedimentary rocks like sandstone, limestone, and shale. \n\nGranite is found in continental land masses. (Granite is NOT a metamorphic rock.) It is an intrusive igneous rock that must cool very slowly to form granite. \n\nHere is a good explanation with some illustrations:\nhttp://www.athro.com/earth_science/rocks.html
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Volcanoes are one of the main ways that igneous rocks are deposited on the surface of the earth. Other igneous rocks form by cooling of magma within the earth and do not reach the surface. These are called intrusive igneous rocks. \n\nOne of the models to explain how our atmosphere was created suggests that volcanic activity released both water vapor and other gases. The present day atmosphere has changed its composition from the original because of the plants that have released oxygen from carbon dioxide.  Current estimates are that volcanic gases contribute 110 million tons of carbon dioxide per year while man's contribution is about 10 billion tons a year. \n\nVolcanoes also contribute other gases and airborne particulates to the atmosphere that can have adverse affects on the environment for several years after a major eruption. Sulphur dioxide is present in most volcanic eruptions and this changes to acid rain as it is dissolved in the atmosphere. This is very harmful to plant life and damages healthy soil. Volcanic ash is often ejected high into the atmosphere and remains there for many years before settling back to earth. This has been speculated to have been the cause of global periods of colder weather  that occured in the 400's and in prior times. \n\nThe formation of intrusive igneous rocks also involves this outgassing of carbon dioxide and other gases, but because it takes place very slowly and often deep underground it has a very gradual effect on the atmosphere. Much of the gas that comes from these rocks will stay traped by being dissolved in water that remains in the subsurface. The movement of this water actually is responsible for many mineral deposits of things like copper ore.
865007
Minerals are what make up rocks.  When Earth's rocks erode, these minerals are released.  A lot of times, erosion takes place in higher elevation areas because the denudation (erosion) rate of higher elevations is also higher than lower elevations and streams usually stem from places of higher elevation.  Minerals then are deposited into these streams.
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Are you serious? ;) Well, I'll try to be:\n\n1. Continents are made up mostly of intrusive or plutonic granitic rocks, oceanic crust of extrusive or volcanic basaltic rocks. Example: compare some Himalayan rock with a hardened lava fragment from Mauna Loa in Hawaii.\n\n2. Continental rocks are lighter and of greater volume - they therefore protrude above the oceanic crust, if you dig very deep down they also have deeper roots. The oceanic crust is denser but thinner.\n\n3. Continental rocks are in general much older. This doesn't mean that oceanic rocks didn't exist before, but they get swallowed up (well, buried real deep and remelted, etc.) in trenches, the deepest parts of the oceans.
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The common name of such a type of rock is obsidian.
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3 basic types of rocks\n\nIgneous Rocks-Igneous rocks are crystalline solids which form directly from the cooling of magma. This is an exothermic process (it loses heat) and involves a phase change from the liquid to the solid state. The earth is made of igneous rock - at least at the surface where our planet is exposed to the coldness of space. Igneous rocks are given names based upon two things: composition (what they are made of) and texture (how big the crystals are).\n\nSedimentary Rocks-In most places on the surface, the igneous rocks which make up the majority of the crust are covered by a thin veneer of loose sediment, and the rock which is made as layers of this debris get compacted and cemented together. Sedimentary rocks are called secondary, because they are often the result of the accumulation of small pieces broken off of pre-existing rocks. There are three main types of sedimentary rocks:\n\nMetamorphic Rocks-The metamorphics get their name from "meta" (change) and "morph" (form). Any rock can become a metamorphic rock. All that is required is for the rock to be moved into an environment in which the minerals which make up the rock become unstable and out of equilibrium with the new environmental conditions. In most cases, this involves burial which leads to a rise in temperature and pressure. The metamorphic changes in the minerals always move in a direction designed to restore equilibrium. Common metamorphic rocks include slate, schist, gneiss, and marble.
210093
Deep within the Earth it is so hot that some rocks slowly melt and become a thick flowing substance called magma. Because it is lighter than the solid rock around it, magma rises and collects in magma chambers. Eventually some of the magma pushes through vents and fissures in the Earth's surface. A volcanic eruption occurs! Magma that has erupted is called lava. \n\nalso\n\nWhen rock inside the Earth becomes hot enough it melts.\nThis molten rock, or magma, is less dense than the surrounding\nsolid rock.  Just as an object that is less dense than\nwater will float on water, the relatively low density of\nthe magma causes it to rise to the surface of the Earth.\n \nIf the magma contains water and dissolved gasses, when\nthe magma reaches the surface the water and dissolved\ngasses will suddenly expand into steam and gas, causing\na violent eruption.  This is like shaking a coke\ncan and then popping the tab.
359180
Chondrites and achondrites is one answer.  Chondrites are the more common form.  But another answer would be "stony" and "iron", of which the stony form is more common.  But of course you can have stony-iron meteorites too...