MINERAL CLASSES

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					MINERAL CLASSES

Mineral are classified according to their chemical compositions. This results in a classification system that
groups minerals with similar properties together. The descriptions below describe the various mineral
classifications:

ELEMENTS
These are pure substances that are not bonded with another type of atom. These are found alone on the
periodic table.
Example: diamond C

SILICATES (Si)
This group makes up 95% of the Earth’s crust. About 2,000 minerals make up this class, therefore this
large category has subdivisions. All silicates contain the silica tetrahedron.

Subgroups:

pyroxenes- single chained (SiO3) n -2                  micas- sheets (Si3O10)n-4

feldspars- 3D framework Si3O8                          amphiboles- double chained (Si4O11)n -6

quartz- 3D framework     SiO2                          olivine- single tetrahedron SiO4 -2



OXIDES- O
An important source of metals. An oxide has a positive ion (cation) bonded to an oxygen. Be careful that
the oxygen is acting alone as the anion.
example- hematite Fe2O


SULFIDES- S
An important source for ore minerals. Sulfides have a cation bonded to sulfur.
example- pyrite FeS2

SULFATES- SO4
These minerals contain the anion (SO4)-2
example- anhydrite CaSO4

CARBONATES- CO3
Contains the complex anion (CO3)-2
example- calcite CaCO3

PHOSPHATES PO4
These minerals are the main source of phosphates for fertilizers. Contain the anion (PO 4)-3
example-

HALIDES
The anion is a halogen, found in column 17 on the periodic table. (F, Cl,Br,I)
example- halite NaCl

				
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posted:12/30/2011
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