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Minerals. Minerals. There are five characteristics that all minerals share: Minerals are NATURALLY OCCURRING Minerals are SOLID Minerals are INORGANIC
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1. Follow-Up from Last Class Define the “population” from which your dust sample was taken
Do you think it was a representative sample?
Were your two samples similar?
How might you sample more effectively?
2. Minerals
3. Minerals There are five characteristics that all minerals share:
Minerals are NATURALLY OCCURRING
Minerals are SOLID
Minerals are INORGANIC
Minerals have specific CHEMICAL COMPOSITIONS
Minerals have specific ATOMIC ARRANGEMENTS
4. Generalized Atomic Structure Nucleus houses the massive particles (protons and neutrons)
# Protons = Atomic Number
# Protons + Neutrons = Atomic Mass
Responsible for mass and density
Electrons lie in orbitals that surround the nucleus
# Electrons = # Protons
If not, then it is an ION
Responsible for bonding
5. Ions Ions are electrically charged particles formed by the gain or loss of electrons
Cations are positively charged
Anions are negatively charged
Metals are elements that readily form cations
Non-Metals are elements that readily form anions
8. Mineral Classes Minerals involve bonds between cations and anions (metals and non-metals)
Only a few elements form common anions(C, N, O, P, S, Cl)
Minerals classified based on anions (non-metals)
9. Elemental Abundance in Crust
12. Most Minerals Are Silicates Crust is mostly Si & O
Crust is made up mostly of minerals that include Si and O
Silicates
13. Silica Tetrahedron The fundamental “architectural” unit of silicate minerals is the silica tetrahedron
One Si ion bonded with four O ions
14. Silica Tetrahedron The silica tetrahedron is a complex ion
An ion that contains a metal cation bound to one or more ions
Overall charge on the silica ion is -4
Charge must be balanced to form a stable mineral
16. Isolated Tetraheda Silicates (Nesosilicates) Tetrahedra do not share any oxygens with neighboring silicon ions
Charge balance achieved by bonding with cations
e.g., Olivine, Garnet
17. Isolated Tetraheda Silicates (Nesosilicates) Is there a distinct shape to the crystal lattice?
What shape will they take when they grow?
Is there a difference in the bonds in different directions?
What shape will they take when they break?
18. Isolated Tetrahedra Silicates
19. Ring Silicates (Cyclosilicates) Sets of tetrahedra share two oxygens to form a ring
Remaining charge balance achieved by bonding with cations
e.g., tourmaline, beryl
20. Ring Silicates (Cyclosilicates) Is there a distinct shape to the crystal lattice?
What shape will they take when they grow?
Is there a difference in the bonds in different directions?
What shape will they take when they break?
21. Ring Silicates
22. Single-Chain Silicates (Inosilicates) Sets of tetrahedra share two oxygens to form a chain
Remaining charge balance achieved by bonding with cations
e.g., pyroxenes
23. Double-Chain Silicates (Inosilicates) Sets of tetrahedra share oxygens (2 and 3 alternation) to form a chain
Remaining charge balance achieved by bonding with cations
e.g., amphiboles
24. Chain Silicates: Habit
25. Chain Silicate Cleavage
26. Chain Silicates: Cleavage
27. Sheet Silicates (Phyllosilicates) Sets of tetrahedra share three oxygens to form a sheet
Remaining charge balance achieved by bonding with cations
e.g., micas, clays
28. Sheet Silicates (Phyllosilicates) Is there a distinct shape to the crystal lattice?
What shape will they take when they grow?
Is there a difference in the bonds in different directions?
What shape will they take when they break?
29. Sheet Silicates Sheet silicates tend to break into sheets and flakes
30. Sheet Silicates
31. Framework Silicates (Tectosilicates) Sets of tetrahedra share all 4 oxygens in 3 dimensions to form a 3-D network
If all tetrahedra are cored by silicon then there is no charge imbalance
e.g., quartz
If some tetrahedra are cored by Al, then the remaining charge balance achieved by bonding with cations
e.g., feldspars
32. Framework Silicates (Tectosilicates) Is there a distinct shape to the crystal lattice?
What shape will they take when they grow?
Is there a difference in the bonds in different directions?
What shape will they take when they break?
33. Framework Silicates
34. Mineral Particulates and Health Which type of silicate will most likely form fibrous particles when broken?
35. Mineral Particulates and Health Which type of silicate will most likely form fibrous particles when broken?Chain Silicates
38. Goldschmidt Classification A classification of the chemical elements into groups according to the part of the Earth where they tend to concentrate
Lithophile elements form silicates or oxides and are concentrated in the crust (e.g., calcium, sodium, magnesium, chromium, titanium)
Siderophile elements form alloys easily with iron and are concentrated in the core (e.g., iron nickel, cobalt, platinum, gold, tin)
Chalcophile elements forms sulfide minerals if sufficient sulfur is available (e.g., copper, zinc, mercury, lead, arsenic, cadmium)
39. Mineral Particulates and Health Which group of elements tends to be most toxic?
Which type of minerals will tend to house the most poisonous elements?
40. Mineral Particulates and Health Which group of elements tends to be most toxic?Chalcophile
Which type of minerals will tend to house the most poisonous elements?Sulfides