Rocks and Minerals

Have you ever wondered about minerals, or how they form?
    A mineral is a naturally occurring, inorganic solid with an orderly crystalline structure with a definite chemical composition. Minerals are not a plant or an animal despite that they are naturally occurring; They are rocks (common), gems, and stones. 

    Minerals form in four different stages starting with crystallization from magma. This is when the magma cools and hardens. Then, the ions and the atoms arrange is the same repetitive form of a pattern. 
    Then on to precipitation. Yet, this is not the normal precipitation that you are used to hearing about. This type is when dissolved minerals in the water form a solid when the water evaporates.
    Pressure and temperature also play a part in the forming of minerals. When the minerals are under extreme pressure and temperature, the minerals then become unstable and are forced to rearrange their ions and atoms to form a different new mineral.
    The last step in the forming of a mineral has to do with hot water and dissolved substances which will cause a chemical reaction with the minerals that were there before to form a new mineral. This process is called Hydrothermal Solutions. 
    Every Mineral has physical properties used to identify them- Color, Streak, Luster, Cleavage, Fracture and Hardness.
    If you were to use color, that would be a poor indicator of minerals because each mineral can have more then one color. Streak is the powered form of a mineral, which is more reliable than color. Luster is the way the light reflects off of a mineral, meaning a mineral can either be Metallic (shiny and looks like metal), or it can be the opposite, Nonmetallic (Earthy, waxy, greasy or brilliant.) Cleavage is the ability for a mineral to break in a predictable pattern due to the arrangement of the atoms. Cleavage is almost the same as fracture, except for the fact that a fracture is the mineral breaking at random. The last physcial property is hardness, which is the resistance for the mineral to be scratched. The Moh's Scale is used to measure the hardness of a mineral from one to ten. For example, Diamond is the hardest mineral, which would make it a 10. Talc, the softest mineral, would be a 1. 



Rocks:

    What are rocks?
    Rocks are any soild mass of mineral or mineral-like matter that occur naturally as part of the planet. There are three main rock classifications, and they are . . .

Igneous:
  

    Igneous rocks form from the melting of magma or the cooling of lava under the Earth's surface. You can find these type of rocks in a volcano or in rifts/ridges. 
    There are two main types of igneous rocks- extrusive and instrusive. Extrusive rocks form when the lava hardens on or near the surface. They usually have small crystals. Intrusive rocks form when the magma hardens beneath Earth's surface, and they usually contain large crystals.
    Igneous rocks are classified using texture. If they are extrusive igneous rocks, they can be glassy and fine. If they are dull and coarse, they are intrusive igneous rocks. Color also classifies the rocks, usually going from light to dark. Density and mass, along with the composition of a rock, can classify them, too.

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Sedimentary:

    Sedimentary rocks are mostly made up of rock pieces all smushed together into layers either by compaction or by cementaion. Compaction is when the weight of the overlying forces pushing particles together. Compaction is where clasts are held together by minerals.
   You will most likley find sedimentary rocks in watery environments.
   When idenifying the looks and/or the features of a sedimentary rocks, there are three different kinds to look for: Fossils, clasts, and stratas. Fossils are the remains of ancient once-living organisms. Clasts are pieces of other rocks. Last but not least, strata are clear layers of sediment. 
   When sedimentary rocks are forming they go through many stages, starting with weathering. Then comes erosion, deposition, compaction and cementation. This happens because the tiny particles of rocks that will soon turn into clay and or pebbles travel down streams and rivers, and eventually, over time, begin to pile up and form sediment. After a long period of time, these layers flatten out and are pressed together, forming a solid rock which is called a sedimentary rock! :)

   Sedimentary rocks are the only rocks where you will find a fossil because sedimentary rocks. Unlike igneous and metamorphic rocks, sedimentary rocks forms at temperatures and pressures that will not destroy or ruin the remains of the once-living organism. However, dead organisms can also become sediments which over time can become a sedimentary rock.
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Metamorphic:
   Metamorphic rocks are formed from extreme heat or pressure, but melting does NOT occur. However, if this rock were to melt, it would turn into an igneous rock. There are two different types of metamorphic rocks. One is a contact metamorphic, which has to deal with a small geographic area. An example is when a rock comes in contact with magma. A regional metamorphic rock occurs over a large geographic area, such as where large mountains form.
   Like sedimentary and igneous rocks, metamorpic rocks have a way of identifying themselves. They can have a distorted structure, which is the foldindg of layers. Foliation, which is the banding of minerals, and are usually black and white. Metaphormic minerals are either granite, dark red, or Mica- which is shiny or flakey.
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ROCK CYCLE:

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