1. 1
Minerals

2. What is a mineral?
►The building block of rocks
 Naturally occurring (versus synthetic)
 Inorganic (no C-H bonds)
 Crystalline solid (ordered internal structure)
 Has a definite but not fixed chemical
composition

3. 02CO, p.20

4. Fig. 2.3b, p.24

5. Chemical composition
of minerals
►Elements
 fundmental component of matter
 Cannot be broken down by ordinary means
►88 naturally occurring elements in Earth’s
crust

6. Chemical composition
of minerals
►8 elements make up 98% of Earth’s crust
 Oxygen
 Silicon
 Aluminum
 Iron
 Calcium
 Magnesium
 Potasium
 Sodium

7. Chemical composition
of minerals
►A few elements ARE minerals (eg: gold)
►Most are comprised of 2 to 5 elements
 Held together by + / - electrical charges
 88 elements form over 3,500 minerals
 9 rock-forming mineral groups

8. Chemical Composition
Mineral Formulas
►Quartz – SiO2 Silicon and Oxygen
►Calcite – CaCO3 (Calcium and Carbon and
Oxygen)
►Olivine – (Fe,Mg)2SiO3 (Iron, Magnesium,
Silicon and Oxygen)
►Potassium Feldspar – KAlSi3O8 (Potassium,
Aluminum, Silicon, and Oxygen)

9. Table 2.1, p.24

10. Crystals

11. Crystals
►Crystal – any substance whose atoms are
arranged in a periodic, repeating pattern
 This pattern is a crystalline structure
 Unit cell – the smallest group of atoms making
up the unique pattern

12. Fig. 2.4, p.25

13. Crystals
►Crystal face – flat surface occurring when a
crystal grows freely
 Reflects light

14. Smaller than the mineral
Atomic size

15. Focus On
►Atom
 Nucleus
►Neutron
►Proton
 Electrons
►Chemical bonds
 Ionic
 Covalent

16. Atoms
►The nucleus of the atom contains protons
and neutrons with electrons surrounding the
nucleus.

17. Atomic Particles
►Proton – positive charge
►Electrons – negative charge
►Neutrons – neutral charge
►Atomic number = the number of protons in
the element
►Atomic mass = the number of protons + the
number of neutrons

18. Chemical Formulas –
Make up of a Mineral
How do I make elements stick to
one another?

19. Bonding
►A link between atoms ( by virtue of the
electrons)
►Na (by itself is a metal) plus Cl (by itself is a
poisonous gas)
►But bonded together it makes NaCl – table
salt
► This is Ionic Bonding – one electron is
transferred to the another

20. NaCl Bonding

21. Bonding
►Carbon Dioxide – CO2
►The atomic bonding is :

22. Covalent Bonding

23. Physical Properties
How can I identify a mineral?

24. 2.4 Physical properties of minerals
►Crystal habit
 the way crystals aggregate
Prismatic quartz crystals and massive quartz with no crystal shape

25. Physical Properties
►Cleavage
 Some minerals tend to break along flat surfaces
due to weak internal bonding
►Fracture
 The way a mineral breaks other than cleavage

26. Physical Properties - Cleavage
►One plane – sheets layered together
►Two planes at right angles – stair stepping
►Two planes not at right angles – roof top
►Three planes at right angles
►Three planes not at right angles

27. Physical Properties
►Hardness – Moh’s scale
 1 to 10, based on minerals
►Specific gravity
 Density relative to water
►Color
 Obvious, but limited use

28. Table 2.2, p.31

29. 2.4 Physical properties of minerals
►Streak
 Color of fine powder
►Luster
 The manner it reflects light
►“Other” properties – smell, taste,
magnetism, striations, and reaction to HCl

30. Mica has a single perfect cleavage plane.

31. Two planes of cleavage
Three planes of cleavage
Four planes of cleavage

32. Fracture – no cleavage

33. Metallic luster of pyrite

34. How Do we Classify
Minerals?
Based on the mineral
assemblages

35. Mineral classes and rock-forming
minerals
► Silicates
► Carbonates
► Sulfides
► Sulfates
► Native elements
► Halides
► Oxides
► Hydroxides
► Phosphates

36. Table 2.3a, p.32

37. Table 2.3b, p.32

38. Mineral classes
►Silicates
 Most abundant rock-forming minerals
 Over 90% of the Earth’s crust contains silicate
minerals
 Basic building block for all silicate
minerals – silica tetrahedra
 Five groups (Si:O ratio, crystal form)

39. Fig. 2.13b, p.33

40. Fig. 2.13a, p.33

41. Fig. 2.14, p.34

42. Mineral Classes
►Carbonates
 Forms many sedimentary rocks
 (CO3)
 Limestone CaCO3

43. Photos of common rock
forming minerals

44. Fig. 2.15a, p.35

45. Fig. 2.15b, p.35

46. Fig. 2.15c, p.35

47. Fig. 2.15d, p.35

48. Fig. 2.15e, p.35

49. Fig. 2.15f, p.35

52. Fig. 2.15i, p.35

53. Some Common Rocks

55. 2.6 Commercially important minerals
►Ore minerals
 Metals or other elements profitably recoverable
Examples – native gold and silver, copper , lead,
zinc
►Industrial minerals
 Non-metals like halite (salt, phosphates, etc)
gypsum (sheetrock), sulfur, apatite
►Gems
 Prized for beauty & rarity, some industrial

56. Fig. 2.18, p.36

57. Fig. 2.17, p.36

58. Fig. 2.19, p.36