1. Mineral

2. Composition of the Crust

3. Minerals are the Chemicals that make up the Earth
NATURALLY-OCCURRING
INORGANIC
CHEMICAL COMPOUNDS
ABOUT 3000 KNOWN
200 COMMON
20 ROCK-FORMING

4. Atomic Bonding
1. IONS

5. Atomic Bonding 2. ELECTRICAL NEUTRALITY (+) and (-) Cancel Out
3. BONDING (SATISFY 1 & 2)
Ionic (NaCl)
Covalent (O2)
Metallic (Cu, Al, Fe)
Hydrogen (in water)

6. Ionic and Covalent Bonding

7. Metallic Bonding

8. Hydrogen Bonding

9. Summary of Bonding Ionic bonding holds rocks and minerals together
Covalent bonding holds people and other organisms together
Metallic bonding holds civilization together
Hydrogen bonding gives water its heat-retaining and solvent properties

10. 4. Lattices
Atoms in crystals form a repeating pattern called a Lattice

11. 5. Radicals
Many minerals contain groups of atoms that behave as single units

12. NAMING MINERALS COLOR Glauconite (Greek: Glaucos = Blue-green)
OTHER PROPERTIES, USES
Magnetite
COMPONENTS
Chromite
PLACES
Muscovite (Moscow)
PEOPLE
Biotite

13. CHEMICALS (AND MINERALS) ARE CLASSIFIED BY THEIR ANIONS

14. For Example: Iron Compounds Have Little in Common
Fe: Gray, Metallic
FeCl2: Light Green, Water Soluble
FeSO4: Light Green, Water Soluble
FeCO3: Brown, Fizzes in Acid
FeS2: Dense, Brittle, Metallic, Cubic Crystals

15. On the Other Hand, Sulfides have Many Properties in Common
FeS2
CuFeS2
PbS
ZnS2
All are Dense, Brittle, Metallic, have Cubic Crystals

16. Identifying Minerals

17. IDENTIFYING MINERALS COLOR -Sometimes Distinctive Often Unreliable
Affected By:
Chemical Impurities
Surface Coating
Grain Size
Weathering

18. IDENTIFYING MINERALS (Continued)
HARDNESS
Resistance to Scratching
Directly related to relative strength of atomic bonds
Scratch Test (Mohs)
Indentation Test (Knoop)
Common Errors due to:
Weathering, ‘Chalk' marks
Breaking vs. Scratching

19. Mohs vs. Knoop Scales Talc: very small Gypsum, Fingernail: 30
Calcite, Penny:
Fluorite:
Apatite:
Feldspar, Glass:
Quartz:
Topaz:
Corundum:
Diamond:

20. IDENTIFYING MINERALS (Continued)
DENSITY
Directly related to masses of component atoms and their spacing
Usually very consistent

21. DENSITY - gm/cm3 (weight relative to water )
Air: Wood - Balsa: 0.1, Pine: 0.5, Oak: Gasoline: 0.7, Motor Oil: 0.9 Ice: Water: Sugar: Halite: Quartz: Most Major Minerals: Aluminum: 2.7

22. DENSITY
Pyrite, Hematite, Magnetite: 5.0 Galena: Iron: Copper: Lead: Mercury: Uranium: Gold: Platinum: Iridium: 22.4 (densest material on Earth)

23. IDENTIFYING MINERALS (Continued)
LUSTER
Metallic or Nonmetallic is the most important distinction.
Resinous, waxy, silky, etc. are self-explanatory.
Vitreous is often used for glassy luster.

24. IDENTIFYING MINERALS (Continued)
CLEAVAGE
Tendency to split along smooth planes between atoms in crystal
Thus directly related to atomic structure
Related to Crystal Form
Every cleavage face is a possible crystal face
Not every crystal face is a cleavage face. Quartz commonly forms crystals but lacks cleavage.

25. IDENTIFYING MINERALS (Continued)
CRYSTAL FORM
Takes Luck & Practice
Well-formed crystals are uncommon
Crystal Classification is somewhat subtle
FRACTURE

26. IDENTIFYING MINERALS (Continued)
GEOLOGIC SETTING
Some minerals occur in all geologic settings: quartz, feldspar, pyrite
Some minerals occur mostly in sedimentary settings: calcite, dolomite
Some minerals occur mostly in igneous settings: olivine
Some minerals occur mostly in metamorphic settings: garnet, kyanite

27. IDENTIFYING MINERALS (Continued)
SPECIAL PROPERTIES
Taste, Magnetism, Etc.
EXPERIENCE AND READING
PROFESSIONAL METHODS
Chemical Analysis
X-Ray Studies
Thin Section

28. Diffraction

29. Diffraction

30. MAJOR MINERAL SUITES ELEMENTS Metallic:Au, Ag, Cu
Not Al, Pb, Zn, Fe, etc.
Nonmetallic: C - Diamond, Graphite
Sulfur

31. MAJOR MINERAL SUITES SULFIDES: Dense, Usually Metallic Many Major Ores
Pyrite FeS2
Chalcopyrite CuFeS2
Galena PbS
Sphalerite ZnS2
Molybdenite MoS2

32. MAJOR MINERAL SUITES HALIDES: Usually Soft, Often Soluble Halite NaCl
Fluorite CaF2
SULFATES: Soft, Light Color
Gypsum CaSO4
Barite BaSO4

33. MAJOR MINERAL SUITES OXIDES: Often Variable, Some Ores Hematite Fe2O3
Bauxite Al(OH) 3 (a hydroxide)
Corundum Al2O3 (Ruby, Sapphire)
CARBONATES: Fizz in Acid, Give off CO2
Calcite CaCO3
Dolomite CaMg (CO3)2

34. MOST IMPORTANT MINERAL SUITE: The Silicate Minerals
Si + O = 75% of Crust
Silicates make up 95% + of all Rocks
SiO4: -4 charge
Link Corner-To-Corner by Sharing Oxygen atoms

35. Nesosilicates - Isolated Tetrahedra
Representatives:
Garnet
Kyanite
Olivine

36. Sorosilicates - Paired Tetrahedra
Epidote is the most common example

37. Cyclosilicates - Rings
Beryl (Emerald)
Tourmaline

38. Single Chains (Pyroxenes)
Inosilicates - Chains
Single Chains (Pyroxenes)

39. Double Chains (Amphiboles)
Inosilicates - Chains
Double Chains (Amphiboles)

40. Phyllosilicates - Sheets

41. Phyllosilicates - Sheets
Si2O5 sheets with layers of Mg(OH)2 or Al(OH)3
Micas
Clay minerals
Talc
Serpentine (asbestos) minerals

42. Tectosilicates - Three-Dimensional Networks
Quartz Feldspars

43. All repeating patterns can be described in terms of repeating boxes
Unit Cells
All repeating patterns can be described in terms of repeating boxes

44. The problem in Crystallography is to reason from the outward shape to the unit cell

45. Which Shape Makes Each Stack?

46. Stacking Cubes

50. Some shapes that result from stacking cubes

51. Symmetry – the rules behind the shapes

52. Symmetry – the rules behind the shapes

53. The Crystal Classes