Review:

      What are the three particles of an atom, where are they found, what are their charges

      What does the octet rule tell us?

      How do ions form?

      What is a cation?

      What is an anion?

      How are covalent and ionic bonding different?

      What controls how big a mineral will grow?

 

Elements bond together to form minerals

Most minerals have ionic and covalent bonds

      Other bonds include:

             van der Waals Bonds

                   Weakest of all bonds

                   Formed by a slight charge difference on molecules

             Metallic bonding

                   Electrons moving around many different atoms of a metal

                   Creates very shiny surface

                   Low hardness

                   High ductility and conductivity

 

Minerals can be defined by chemical composition

      What are chemical formulas and what do they tell us?

             Each mineral is defined by a specific chemical formula

                   Quartz SiO2,  (covalent bond)

                   Halite NaCl,    (ionic bond)

                   Olivine (Mg,Fe)2SiO4  (covalent & ionic)

 

Elements and abundance in Crust

      Element            Weight %

      Oxygen            46.6

      Silicon              27.7

      Aluminum        8.1

      Iron                  5.0

      Calcium            3.6

      Sodium             2.8

      Potassium         2.6

      Magnesium       2.1

                               98.5%

 

7 mineral groups

      Each group is defined by a specific chemical constituent

             First 6 groups make up the ore minerals

             Last group is the rock forming minerals

 

 

Group 1 Carbonates

      Carbonate ion combines with cation 

             Carbonate ion:  CO32-

EX// Calcite

             CaCO3

      Malachite

             (CuCO3 (OH)2)

A few other carbonates

      Rhodochrosite:

             Occurs in hydrothermal veins with ore of silver, lead and copper

             Used for ornamental

             Ore of manganese

      Azurite:

             Occurs with malachite

             Copper ore

 

Group 2   Oxides:

      Oxygen combines with a metal

             Oxygen ion (O2-)

                   ex//  Hematite  Fe2O3

                         Ore of iron, use as gems, dye

                   Bauxite Al(OH)3

                   Corundum (Al2O3)

                         Rubies & sapphires

                         Igneous and met rx

 

Group 3  Sulfides:

      Sulfur ion combines with a metal

             Sulfur ion (S2-)

                   Galena (PbS) (lead)

                   Pyrite (FeS2) (iron)

                   Cinnabar (HgS) (mercury)

                   Realgar (AsS) (arsenic)

 

Group 4 Sulfates:

      Sulfate ion (SO42-)

             Barite (barium)

                   BaSO4

             Celestite  (Strontium)

                   SrSO4

             Gypsum (calcium)

                   CaSO4 2H2O

 

Group 5

      Halides:

             A metal  and non-metal ionically bonded

                   Fluorite CaF2

                   Halite NaCl

 

Group 6

      Native elements

             Gold, silver, copper etc…

                   Forms in igneous environments

                   Associated with granite

             Sulfur

                   Associated with volc.

 

Ore minerals in the NW…see map.