Rocks and Minerals

Hi Guys! This is the second article about Earth Science. In this article we would be discussing a little bit about minerals. I hope that you find what I put useful. 


Minerals
   is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not have a specific chemical composition. Minerals range in composition from pure elements and simple salts to very complex silicates with thousands of known forms. The study of minerals is called mineralogy.

1. Naturally occurring

2. Solid substance

3. Orderly crystalline structure

4. Definite chemical composition

5. Generally considered inorganic

How Minerals Form

   1. Crystallization from magma

   2. Precipitation

   3. Pressure and temperature

   4. Hydro thermal solutions 

Mineral Groups

    Can be classified based on their composition

          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 metal element.

                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

       Properties of Minerals

 1. Color    -  Small amounts of different elements can give the same mineral different colors.

2. Streak   -  is the color of a mineral in its powdered form.

3. Luster   -  is used to describe how light is reflected from the surface of a mineral.

4. Crystal Form   -  is the visible expression of a mineral’s internal arrangement of atoms.

5. 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).

6. Cleavage   -  is the tendency of a mineral to cleave, or break, along flat, even surfaces.

7. Fracture   -  Minerals that do not show cleavage when broken are said to fracture.

                       -  the uneven breakage of a mineral

8. Density    - is a property of all matter that is the ratio of an object’s mass to its volume.

The Importance of Rocks and Minerals Name Type of Rock Use Basalt Igneous Used in road building materials Calcite Mineral Used in cements and mortars and the production of lime Granite Igneous Used for buildings, monuments, and tombstones Marble Metamorphic Used in building, floors, tile in bathrooms Obsidian Igneous Used in making arrowheads and knives Pumice Igneous Used in scouring, scrubbing, and polishing materials Quartz Mineral Used in making glass, electrical components, and optical lenses Sandstone Sedimentary Used in the building industry for houses Slate Metamorphic Used for roofs, chalkboards, and patio walks

Source: http://library.thinkquest.org/J002289/uses.html

I hope that what I wrote help you a little bit.

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Checked by Prof. Crisencio Paner