Geology

A:

The specific type of rock that forms when magma cools at the Earth's surface is extrusive igneous rock. Igneous rock forms when magma cools, but where the magma cools determines the type of igneous rock that forms. Igneous rock gets its name from the Greek word for fire and is so called due to the extremely hot liquid from which the rocks originate.

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  • How Is Sandstone Formed?

    Q: How Is Sandstone Formed?

    A: Sandstone forms over the course of centuries, as deposits of sand accumulate in rivers, lakes or on the ocean floor, and the sand blends with calcite or quarts and then undergoes compression. After enough time goes by, the pressure pushes all of these elements together to create sandstone. Because not all sand is identical but instead comes in a variety of colors and grain textures, each formation has a unique appearance.
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  • What Are Igneous Rocks Used For?

    Q: What Are Igneous Rocks Used For?

    A: Igneous rocks are often used for construction because of their durability. Igneous rocks can also be separated to access the various valuable metals and minerals inside them. Igneous rocks form as magma comes to or near the surface of the Earth; cooling and hardening because of its distance from the inner parts of the Earth where magma forms.
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  • What Is a Mineral Resource?

    Q: What Is a Mineral Resource?

    A: A mineral resource is the concentration of materials that are of economic interest in or on the crust of the Earth. Almost all minerals found on Earth are used in one way or another for economic benefit. Examples of minerals include gold, gravel, sand, aluminum, copper, limestone, clay and diamond.
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  • What Are Metamorphic Rocks Used For?

    Q: What Are Metamorphic Rocks Used For?

    A: Metamorphic rocks are used for roofing material, decorative gardening stone, the base for snooker tables, building material, sculpture material and paving material. Metamorphic rocks come in three different types: slate, marble and schist.
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  • How Is a Plateau Formed?

    Q: How Is a Plateau Formed?

    A: A plateau is formed by a process of geological uplift, either due to the collision of continental plates, pressure from magma below or the burial of land by volcanic lava and ash flows, resulting in a high, flat surface. These are very similar to processes that give rise to mountains and mountain ranges. The only major difference is that a plateau is flat while mountains are peaked.
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  • How Are Meteorites Formed?

    Q: How Are Meteorites Formed?

    A: Most meteorites that fall to Earth come from the asteroid belt between Mars and Jupiter, where they formed during the early days of the solar system. Occasionally, collisions or gravitational perturbations send one of these objects hurtling toward the sun. If it approaches close to Earth, it may fall into the planet's gravity well.
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  • How Do You Turn Copper Green?

    Q: How Do You Turn Copper Green?

    A: To turn copper green, create a verdigris paina by rubbing the metal with a vinegar and salt solution. Before you begin, gather some steel wool, a bowl, paper towels, dish soap, baking soda and a finishing wax or lacquer.
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  • What Is Clay Soil?

    Q: What Is Clay Soil?

    A: Clay soil is composed of tiny particles that are hard and able to become easily compacted. This compaction makes it difficult to plant or even shovel within the soil.
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  • What Is Dry Lava Called?

    Q: What Is Dry Lava Called?

    A: Dry lava is called igneous rock. The superheated molten rock that reaches the surface in an eruption is called lava, and lava may flow for miles before cooling.
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  • How Much Is Topaz Worth?

    Q: How Much Is Topaz Worth?

    A: The market value of topaz varies greatly, ranging from approximately $8 to $749 per carat as of September 2014. Its worth is determined by a number of factors such as weight, color, clarity, cut and shape. A gemologist must appraise the gem to provide an exact estimate.
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  • How Is an Isthmus Formed?

    Q: How Is an Isthmus Formed?

    A: Isthmuses, which are narrow strips of land connecting two land masses and separating two bodies of water, are formed in various ways, depending on the geology of the areas in which they occur. These geological changes to form isthmuses may involve the movement of tectonic plates, the drowning of landmass due to fault structures, volcanic activity, and the movement of waves and tides.
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  • What Is the Parent Rock of Gneiss?

    Q: What Is the Parent Rock of Gneiss?

    A: Possible parent rocks of gneiss are granite, shale, gabbro or diorite. Some rocks metamorphose, or change, from one particular kind of rock, but gneiss forms from one of several types. Another name for the parent rock is the protolith.
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  • What Is the Outer Core?

    Q: What Is the Outer Core?

    A: The outer core is part of the core, which is one of the three major layers of the Earth. The core is the deepest and hottest layer and is mostly composed of metals, and it is beneath the Earth's mantle. The outer core is the first layer of the core, and it extends to a depth of approximately 2,890 kilometers below the Earth's crust and measures 2,300 kilometers thick.
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  • What Is the Difference Between Soil and Sand?

    Q: What Is the Difference Between Soil and Sand?

    A: Soil is made up of liquids, solids and gases that form on the surface of land, while sand is a natural material that consists of at least 85 percent sand-sized particles. Soil consists mostly of organic matter, such as decomposing animals and plants and minerals. The most common sand found throughout the world is made up of quartz, or silicon dioxide.
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  • What Is Sedimentary Rock?

    Q: What Is Sedimentary Rock?

    A: Sedimentary rocks are formed by the deposition of mud, clay, sand and other small particles on the surface of the Earth. Sedimentation can occur in many different environments, including lakes, rivers, deserts and oceans. The sediment is deposited in layers that are compressed over time and turned into solid rock.
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  • How Do Fossil Fuels Form?

    Q: How Do Fossil Fuels Form?

    A: Fossil fuels are formed the gradual accumulation of organic remains on the sea floor. As the accumulation rate increases, the organic remains are subjected to heat and pressure, which leads to fossil-fuel formation.
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  • Is Salt a Non-Renewable Resource?

    Q: Is Salt a Non-Renewable Resource?

    A: Salt, or sodium chloride, is a non-renewable resource. A resource is defined as renewable only if it is self-replenishing. While new salt is being formed by natural processes in the earth, the timescale for that formation is too vast for salt to be considered self-replenishing in terms of human use.
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  • What Rock Is Formed When Magma Cools at the Earth's Surface?

    Q: What Rock Is Formed When Magma Cools at the Earth's Surface?

    A: The specific type of rock that forms when magma cools at the Earth's surface is extrusive igneous rock. Igneous rock forms when magma cools, but where the magma cools determines the type of igneous rock that forms. Igneous rock gets its name from the Greek word for fire and is so called due to the extremely hot liquid from which the rocks originate.
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  • What Is a Mine-Cut Diamond?

    Q: What Is a Mine-Cut Diamond?

    A: Mine-cut diamonds are typically square or slightly oval and have a deeper crown and pavilion, or top and bottom, than modern stones. "Mine cut" does not refer to the place the diamond was faceted, but rather to its overall shape and brilliance.
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  • Why Is a Diamond so Hard?

    Q: Why Is a Diamond so Hard?

    A: The molecular structure of a diamond makes it hard, as diamonds are comprised of carbon atoms linked closely together in a lattice structure. The atoms are linked tightly via covalent bonds wherein two atoms share an electron. A tetrahedral unit is composed of five carbon atoms, with one carbon atom sharing electrons with the other four. An extremely strong molecule is formed from the tetrahedral bonding of five carbon atoms.
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  • Where Is Coal Found?

    Q: Where Is Coal Found?

    A: Coal reserves exist in every country in the world and on every continent except Antarctica. According to the World Coal Association, there are enough coal reserves to meet current demand for 112 years, but only enough oil and gas reserves to meet current demand for the next 46 and 54 years, respectively.
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