Huwebes, Hunyo 21, 2012

Minerals and Rocks



I learned many things about natural science that formed the earth, It took time to create beautiful forms of rocks and minerals that we can treasure and take care of .

Minerals

There are Over 100 Elements are the basic building blocks of minerals.


Atoms
Smallest particles of matter
Have all the characteristics of an element
The nucleus is the central part of an atom and contains
        protons, which have positive electrical charges
        neutrons, which have neutral electrical charges
       Energy levels, or shells
        surround the nucleus
        contain electrons—negatively charged particles

The atomic number is the number of protons in the nucleus of an atom.

Atoms Bond when an atom’s outermost energy level does not contain the maximum number of electrons, the atom is likely to form a chemical bond with one or more atoms.
        A compound consists of two or more elements that are chemically combined in specific proportions.
          An ion is an atom that gains or loses electrons.


The Three Types of Chemical Bonds are Ionic bonds form between positive and negative ions, Covalent bonds form when atoms share electrons and Metallic bonds form when metal ions share electrons.


 Mineral is:
1. Naturally occurring
  2. Solid substance
 3. Orderly crystalline structure
   4. Definite chemical composition
   5. Generally considered inorganic

  Minerals Form by
        1. Crystallization from magma
        2. Precipitation
        3. Pressure and temperature
        4. Hydrothermal solutions

Mineral Groups
        1. Silicates
        Silicon and oxygen combine to form a structure called the silicon-oxygen tetrahedron. This silicon-oxygen tetrahedron provides the framework of every silicate mineral.
        2. Carbonates
        Minerals that contain the elements carbon, oxygen, and one or more other metallic elements
        3. Oxides
        Minerals that contain oxygen and one or more other elements, which are usually metals
  4. Sulfates and Sulfides
        Minerals that contain the element sulfur
  5. Halides
        Minerals that contain a halogen ion plus one or more other elements
  6. Native elements
        Minerals that exist in relatively pure form


There are different Properties of mineral that helps us know their characteristics like:
Color
         Small amounts of different elements can give the same mineral different colors.
            Streak
      Streak is the color of a mineral in its powdered form.
    Luster
       Luster is used to describe how light is reflected from the surface of a mineral.
  Crystal Form
      Crystal form is the visible expression
of a mineral’s internal arrangement of atoms.
    Hardness
        Hardness is a measure of the resistance of a mineral to being scratched.
        Mohs scale consists of 10 minerals arranged from 10 (hardest) to 1 (softest).
     Cleavage
         Cleavage is the tendency of a mineral to cleave, or break, along flat, even surfaces.
      Fracture
         Minerals that do not show cleavage when broken are said to fracture.
         Fracture—the uneven breakage of
a mineral
     Density
         Density is a property of all matter that
is the ratio of an object’s mass to its volume.
                 
Distinctive Properties of Minerals
         Some minerals can be recognized by other distinctive properties.
         

    Rocks

         Rocks are any solid mass of mineral or mineral-like matter occurring naturally as part of our planet.


       Types of Rocks
        1. Igneous rock is formed by the crystallization of molten magma.
        2. Sedimentary rock is formed from the weathered products of preexisting rocks that have been transported, deposited, compacted, and cemented.
        3. Metamorphic rock is formed by the alteration of pre-existing rock deep within Earth (but still in the solid state) by heat, pressure, and/or chemically active fluids.

        The Rock Cycle
         Shows the interrelationships among the three rock types (igneous, sedimentary, and metamorphic)
         Magma is molten material that forms deep beneath the Earth’s surface.
         Lava is magma that reaches the surface.
         Weathering is a process in which rocks are broken down by water, air, and living things.
         Sediment is weathered pieces of Earth elements.
       Energy That Drives the Rock Cycle
         Processes driven by heat from the Earth’s interior are responsible for forming both igneous rock and metamorphic rock.
         Weathering and the movement of weathered materials are external processes powered by energy from the sun.
         External processes produce sedimentary rocks.

       Formation of Igneous Rocks
        1. Intrusive igneous rocks are formed when magma hardens beneath Earth’s surface.
        2. Extrusive igneous rocks are formed when lava hardens.
        Classification of Igneous Rocks
         Igneous rocks can be classified based on their composition and texture.
          Coarse-grained texture is caused by slow cooling resulting in larger crystals.
       1. Texture
        •  Fine-grained texture is caused by rapid cooling resulting in smaller, interconnected mineral grains.
        2. Composition
       •  Granitic composition rocks are made mostly
of light-colored quartz and feldspar.
  

   Formation of Metamorphic Rocks
         Metamorphism means “to change form.”
         Most metamorphic changes occur at elevated temperatures and pressures.
        Conditions for formation are found a few kilometers below the Earth’s surface and extend into the upper mantle.

Classification of Metamorphic Rocks
 Two main categories
1. Foliated Metamorphic Rock
        Has a banded or layered appearance
2. Nonfoliated Metamorphic Rock
               Does not have a banded texture 


We watched videos about minerals and rocks  that shows the different colors of it and there different classifications

thanks to Professor Crisencio Paner I learned so much things about nat sci :) 




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