you find a rock that is made of small grains?how can you tell whether it is igneous or sedimetary?
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you need to see whethre the "grains " ae INTERLOCKING, or fixed togethre with a cement. Interlocking grains, whee there are no spaces between them (the "grains" wi be crstals of quartz, felspar and ther minerals depending on type of rock) are indicative of an igneous rock. (or metamorphic) rock. sdimentar rocks are generally made of "clasts" or grains cemented together with a matrix or cement. here are some exceptions to this like evaporites, eg rock salt.
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In a phrase, volcanic rock.\n\nEach volcano erupts constructively and destructively, and some of those constructive eruptions build the sides of the volcano.  The type of magma determines the color and shape.
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Greetings,\n\nSedimentary rocks have many uses.\n\n1.  Fossils are found in sedimentary rocks.  By analyzing the composition and age of the rock they are able to determine when the animal that made the fossil lived.\n\n2. Limestone and sandstone are two kinds of sedimtary rocks.  If you've ever drank from a cool crisp mountain stream you've probably drank water filtered through limestone or sandstone.\n\n3. Visit the badlands of North or South Dakota in the U.S. and you'll see sedimtary rock of immense beauty.\n\nThere are more uses I'm sure, but I'm supposed to be working.  Good luck with your question.\n\n-matt
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whitish/grayish. It's really just made up of rock. Then again its just a humongous rock that's in orbit with us.
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Igneous rocks are formed when molten rock (magma) cools and solidifies, with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. This magma can be derived from either the Earth's mantle or pre-existing rocks made molten by extreme temperature and pressure changes. Over 700 types of igneous rocks have been described, most of them formed beneath the surface of the Earth's crust. The word "igneous" is derived from the Latin ignis, meaning "fire".\n\nIgneous rock are classified according to mode of occurrence, texture, chemical composition, and the geometry of the igneous body.\n\nIgneous rocks make up 95% of the Earth's upper crust.
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1. The difference between rocks & minerals\nhttp://www.rocks-and-minerals.com/ gives a simple but good explanation of the difference between rocks & minerals.\n\nIt is not easy to tell the difference between rocks & minerals because there are so many kinds of them. It takes years of study to be able to accurately identify a mystery rock and even then rockhounds want to know where the specimen came from. \n\nRocks\nAll rocks are made of 2 or more minerals, but minerals are not made of rocks. To see some pictures of different kinds of rocks, click here.\n\nRock Words: There are many common names for rocks and the usually give you an idea of how big the rock is. Here are a few:\n boulder - large, taller than a person \n rock - large, you could get your arms around it or a bit smaller but it is usually jagged, broken off a bigger piece of rock  \n river rock - round rocks that are along the edge & at the bottom of fast-flowing rivers  \n stone - medium, you could hold it in two hands  \n pebble - small, you can hold it with two fingers, could get stuck in your shoe, usually rounded  \n sand - made up of tiny pieces of rock, grains of sand  \n grain - tiny, like a grain of rice or smaller, often found on a beach  \n dust - really fine powder that is mixed in with sand or soil  \n mountain - huge, giant hunk of rock that is still attached to the earth's crust, doesn't move, tall  \n\n\nFor an excellent Rock Identification test, click on http://www.bwctc.northants.sch.uk/html/projects/science/ks34/rocks/key.html\n\n \n\nMinerals\nA mineral is the same all the way through. That is one reason we speak of a sample or a specimen rather than a rock. There are about 3000 known minerals on earth. Al rocks are made up of 2 or more of these minerals. To find out more about different kinds of minerals, click here.
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Rock is a naturally occurring aggregate of minerals and/or mineraloids. Rocks are classified by mineral and chemical composition; the texture of the constituent particles; and also by the processes that formed them. These indicators separate rocks into igneous, sedimentary, and metamorphic.\n\nMinerals are natural compounds formed through geological processes. The term "mineral" encompasses not only the material's chemical composition, but also the mineral's structure. Minerals range in composition from pure elements and simple salts to very complex silicates with thousands of known forms (organic compounds are usually excluded)
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1) Rhyolites that cool too quickly to grow crystals form a natural glass or vitrophyre, also called obsidian\n\n2) amount of silica di-oxide, texture and color\n\n3) gold is found in quartz veins around igneous intrusion via hydrothermal fluid precipitation\n\n4) If we assume a slower but constant rate of cooling, then both minerals could feasibly form well shaped crystals at the same time (phaneritic texture) .  If we assume a slow than fast cooling, then possibly only plagioclase would form (porphyritic texture) due to its position in Bowen's reaction series.
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One way to distinguish between intrusive and extrusive igneous rocks is to observe the crystal size.\nRocks formed below groung (intrusive) have must longer to cool, resulting in a larger crystal size.\nOn the other hand, rocks formed above ground (extrusive) have a much smaller crystal size
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* rock - mineral matter of variable composition, consolidated or unconsolidated, assembled in masses or considerable quantities in nature, as by the action of heat or water. \n* Igneous rock - rock formed by the solidification of molten magma\n* metamorphic rock - rock altered by pressure and heat\n* sedimentary rock - rock formed from consolidated clay sediments
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These are igneous rocks.
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We are dealing with an illusion caused by grain size and moisture content here.  In fact sand is quite hard because it is made up of individual rock and mineral grains.  Limestone and quartz are pretty hard materials.  If a sand is damp, or has very small rounded grains, it can feel soft to the hand however.\n\nClays on the other hand are soft because they are created by the chemical weathering of other minerals (such as pyroxene or feldspar) and the individual clay units are microscopic in size.  Clays usually contain a high proportion of water in their structure as well (it can be as high as 70%).\n\nWhen a geologist in the field can't make out the whether a rock is a siltstone (clastic) or clay (chemical) because the grain sizes are too small to see, a simple test is to break off a small fragment put it between ones teeth.  If its chewy and soft, its a clay.  If its hard and gritty, its a silt. \n(Warning - experts only folks.  Some rocks contain poisonous minerals so don't go around randomly tasting rocks.)
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well, do you have access to a stone saw?  Look for crystalline structure inside of the object.  Also determine it's specific gravity, and you can look it up on the jpl web site.  First though is it metal, magnetic? Or a rock.
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Igneous rocks-- formed from magma, extrusive or intrusive.  extrusive have small crystal forms ex. basalt, scoria, pumice.  Intrusive large crystals forms ex. granite, gabbro\n\nSedimentary rocks -- the only rocks that contain fossils, formed at the surface, formed from fragments of other things ie. rocks, fossils, woody plants (coal), or minerals crystallizing out of water (limestone) -- Are porous found in aquifers, oil fields.\n\nMetamorphic rocks -- forms from alteration of other rock with increased pressure and/or temperature.  Always in a solid state (they don't melt)called recrystallization, form new minerals that are stable at increased temperature and/or pressure, happens below the earth's surface (at depth).
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Igneous.  Not sedimentery because those are made up of worn down other rocks, and not metamorphic because they are rocks that were originially another sort of rock.
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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.
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The rocks are no problem. You can go outside & find those.\n\nIgneous rocks include granite & diorite which are relatively easy to find. They are commonly used around driveways & railroad tracks.\n\nSedimentary rocks can be shale, sandstones, conglomerates, limestone, mudstones, etc. Depending on where you live it may be harder to find these.\n\nMetamorphic rocks might also be a problem unless you live somewhere near the mountains. If you have a piece of marble or slate used in flooring & countertops, they are easier to get a hold of.\n\nThe fossils are harder to get unless you actually go out to a riverbed or live near a site known to contain fossils. Your best bet would be to search the net for a reputable dealer or find a store near where you live.\n\nHappy rock & fossil hunting & good luck on the project. :)