Geology

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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 Is Absolute Dating?

    Q: What Is Absolute Dating?

    A: Absolute dating is a method of determining the specific date of a paleontological or archaeological artifact or location based on a specific time scale or calendar. Scientists base absolute dating on measurable physical or chemical changes or on written records of events.
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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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  • 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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  • How Are Minerals Formed?

    Q: How Are Minerals Formed?

    A: Minerals are formed under a variety of conditions, including when molten materials cool, when liquids evaporate or cool and under high temperatures and pressures. Minerals are found in the earth's crust and mantle, and many were created when feldspar and quartz reacted with other materials during the formation of the planet.
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  • How Much Does a Grain of Sand Weigh?

    Q: How Much Does a Grain of Sand Weigh?

    A: An average grain of sand weighs approximately 50 micrograms, and a grain of very fine sand can weigh as little as 350 nanograms. The size of grains of sand vary because they are not uniform.
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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 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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  • How Deep Is Lake Huron?

    Q: How Deep Is Lake Huron?

    A: The average depth of Lake Huron is approximately 195 feet, but its deepest point reaches 750 feet below the surface. This massive body of water is located between Michigan and Canada, stretching 206 miles long and 183 miles wide.
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  • What Is Exfoliation Geology?

    Q: What Is Exfoliation Geology?

    A: Exfoliation geology is a type of rock weathering where the rock's layers peel off in whole sheets instead of grain by grain. Large-scale exfoliation occurs due to the mechanics of gravity on a curved surface, while small-scale exfoliation is due to chemical weathering.
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  • How Is Quartz Mined?

    Q: How Is Quartz Mined?

    A: The Encyclopedia of Arkansas explains that commercial mining of quartz is rare and occasionally consists of the use of explosives to first expose the quartz, followed by the operation of small hand tools such as chisels and rock picks to extract portions of the mineral from a quarry. Quartz is quite sensitive to temperature changes, so miners prefer not to use explosives unless absolutely necessary.
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  • What Is the Importance of Geology in Civil Engineering?

    Q: What Is the Importance of Geology in Civil Engineering?

    A: Geology is the study of earth, the materials of which it is made, the structure of those materials and the effects of the natural forces acting upon them and is important to civil engineering because all work performed by civil engineers involves earth and its features. Fundamental understanding of geology is so important that it is a requirement in university-level civil engineering programs.
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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 Petrified Fossils Form?

    Q: How Do Petrified Fossils Form?

    A: According to the Oxford University Museum of Natural History, petrified fossils form when mineral deposits replace the bones of dead creatures inside hardened sediment. Over time, these deposits completely replace the remains, forming an image of the bones out of solid rock.
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  • What Is the Biggest Rock in the World?

    Q: What Is the Biggest Rock in the World?

    A: According to About.com, Mount Augustus is the biggest rock in the world. This monolith is located in Western Australia's Golden Outback, 286 miles east of Carnarvon.
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  • Where Do Rocks Come From?

    Q: Where Do Rocks Come From?

    A: Rocks come from magma, which is the molten material found within the earth. When magma cools, either above or below the earth's surface, it crystallizes and forms the igneous rocks that can later be changed into metamorphic or sedimentary rocks. Magma, which can be considered molten rock, is referred to as lava when it reaches the earth's surface.
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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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  • 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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  • 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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  • How Is Shale Formed?

    Q: How Is Shale Formed?

    A: Shale forms from the pressure of layers of sediment compressing bits of silt that settle into the clay on the bottom of bodies of water. The compressed clay and silt become shale over time. Shale is a sedimentary rock.
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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 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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