1. BELL WORK: Define MINERAL:
TODAY: Intro to MINERALOGY

2. EXAMINE EACH SAMPLE
Please be careful! Some minerals are very delicate and will break
Using as many senses as possible – please completely describe each sample in your notebook
for example: “gold and shiny, looks like corn flakes stuck on a rock, sharp edges, heavy..”
Write the descriptions as a cheat sheet in case you have to identify them again…

3. MINERALOGY: BELL WORK – watch the video and tell me what accounts for the color variation in the diamonds. (Remember the chemical formula for diamonds – C )
Diamonds
Gems
What is a mineral

4. ATOMS, ELEMENTS & MINERALS
PART I – BASIC CHEM REVIEW
PART II – CRYSTALLINE STRUCTURES
PART III – PHYSICAL PROPERTIES

5. ATOMS AND ELEMENTS
An element is a substance that can not be broken down into others by ordinary chemical reactions
An atom is the smallest unit of a substance that retains the properties of that element
Composed of 3 types of subatomic particles
Protons (positively charged)
Neutrons (zero net charge)
Electrons (negatively charged)
A molecule is the smallest unit of a compound that retains the properties of that substance

6. ATOMS AND ELEMENTS
92 naturally occurring elements (specific arrangements of atoms)
Atomic number = number of protons
Mass number = number of protons and neutrons
Isotopes – same atoms w/ different number of NEUTRONS but the same number of protons in each atom.

7. Atomic Structure Protons and neutrons form the nucleus of an atom
Represents tiny fraction of the volume at the center of an atom, but nearly all of the mass
Electrons constantly move and occupy space around the nucleus in discrete shells or energy levels
Shells represent nearly all of the volume of an atom, but only a tiny fraction of the mass
Numbers of electrons and protons are equal in a neutral atom
Ordinary chemical reactions involve only outermost shell (valence) electrons
The most stable configuration for an atom is when each energy level is completely filled.

10. BELL WORK
List the most abundant elements on Earth’s crust in order from most to least.

11. Composition of Earth’s Crust
Common elements
Nearly 97% of the atoms in Earth’s crust are represented by the 8 most common elements
Minerals have crystalline structures
Regular 3-D arrangement of atoms
Common mineral types
Most minerals are silicates (contain Si and O bonded together)
Insert Box Fig. 2A here

12. ANSWERS O – 46.6 Si – 27.7 Al – 8.1 Fe – 5.0 Ca – 3.6 Na – 2.8 K – 2.6
Mg – 2.1
Other – 1.5
MAKE UP YOUR OWN ACRONYM FOR THESE

13. WHAT is a CRYSTAL?

14. Crystalline Substance
All atoms are arranged in an orderly, regularly repeating, 3 dimensional pattern.

15. WHAT is a Mineral?
Come up with a definition…. Do you remember the movie last week?

16. MINERALS
Defined as an inorganic, naturally occurring, crystalline structure that is physically and chemically distinctive.
Have specific chemical formulas
Quartz has twice as many oxygen than silicon atoms.
i.e.; Quartz = SiO 2

17. MINERALS INTRODUCTION
Each mineral is:
Compositionally and physically distinctive
Develops in a particular way
Distinguished by a combination of properties
A crystalline substance
The arrangement of atoms are orderly and regular

18. MINERALS
Defined as an inorganic, naturally occurring, crystalline structure that is physically and chemically distinctive.
Have specific chemical formulas
Quartz has twice as many oxygen than silicon atoms.
i.e.; Quartz = SiO 2

19. END OF SECTION 1 Read text pages 29 – 33.
We will be going over Ions and Crystalline Structures in the next lecture.
Start terms in your notebook pg. 53 – they will all be due next week.

20. Minerals A mineral must meet the following criteria:
Crystalline solid
Atoms are arranged in a consistent and orderly geometric pattern
Forms through natural geological processes
Has a specific chemical composition
May include some internal compositional variation, such as the solid solution of Ca and Na in plagioclase)
Rock-forming minerals
Although over 4000 minerals have been identified, only a few hundred are common enough to be generally important to geology (rock-forming minerals)
Over 90% of Earth’s crust is composed of minerals from only 5 groups (feldspars, pyroxenes, amphiboles, micas, quartz)

21. MINERALS NON SILICATES SILICATES NOT ABUNDANT VERY ABUNDANT Halides
Carbonates
Sulfates
Sulfides
Oxides
Native elements
SILICATES
VERY ABUNDANT
Vary from simple to complex arrangements of Silica

23. Silica Silicon and oxygen combined
Silicon is the 2nd most abundant element on earth so most minerals contain silica.
Mineral substances that contain silica are called silicates.

24. Silicon – Oxygen Tetrahedron
4 oxygen atoms (anions)
1 silicon atom
Each corner represents the center of an oxygen atom
Basic building block of a silicate mineral

25. Silicon – Oxygen Tetrahedron
Formula SiO4 ‾‾ 4
Silicon has a charge of +4
4 oxygen have 8 negative charges (-2 for each)
Can bond with positively charged ions , like Al or Fe (balanced by enough + charged ions)
OR w/ other S-O-T’s.
So for it to be stable it must share + ions or share oxygen w/ adjacent tetrahedrons (reduce the need for extra + charged ions)

26. Silicate Structures – Page 39
Sharing of O atoms in tetrahedra
The more shared O atoms per tetrahedron, the more complex the silicate structure
Isolated tetrahedra (none shared)
Chain silicates (2 shared)
Double-chain silicates (alternating 2 and 3 shared)
Sheet silicates (3 shared)
Framework silicates (4 shared)

27. VIDEO

29. Isolated Silicate Structures- NEOSILICATES
Silicate minerals are structured so that none of the O atoms are shared by tetrahedrons.
The isolated silicate structure is bonded by positively charged ions (fig. 2.9)
EX: Olivine (Mg,Fe)2SiO4 contains ions of either Fe+2 or Mg+2 for each S-O-T.

30. Nesosilicates
Phenacite-- Be2(SiO4) Willemite-- Zn2(SiO4) Olivine--(Fe, Mg)2(SiO4) Garnet-- A3B2(SiO4)3 Zircon-- Zr(SiO4) Andalusite--Al2 SiO5 Sillimanite-- Al2 SiO5 Kyanite-- Al2SiO5 Topaz-- Al2(SiO4)(F, OH)2 Staurolite-- Fe2Al9O6 (SiO4)4(O, OH)2 Chondrodite--Mg5(SiO4)2(F, OH)2 Datolite--CaB(SiO4)(OH) Sphene--CaTiO(SiO4)

31. Sorosilicates
The sorosilicates are characterized by isolated double silicate tetrahedra that share an oxygen.

32. Sorosilicates
Common Sorosilicate Minerals Hemimorphite-- Zn4(SiO4) Lawsonite--CaAl2(Si2O7)(OH).(H2O) Clinozoisite--Ca2Al3(SiO4)(Si2O7)(OH) Epidote-- Ca2(Al, Fe)(Al2O)(SiO4)(Si2O7)(OH) Idocrase--Ca10 (Mg, Fe) 2Al4(SiO4)5(Si2O7)(OH)7 Prehnite-- Ca2Al2(Si3O10)(OH)2

33. Chain Silicates
Structures form when two tetrahedron’s O is shared w/ adjacent tetrahedrons to form a chain (net –charge)

34. Single Chain Ionosilicates– PYROXENE GROUP
Single chain – Silicon to Oxygen, 1:3, so each mineral in this group incorporates SiO3 -2 in its formula and must be balanced by + ions that holds parallel chains together.

35. Single chain inosilicates
Pyroxene group
Diopside - hedenbergite series
Diopside - CaMgSi2O6
Hedenbergite - CaFeSi2O6
Augite - (Ca,Na)(Mg,Fe,Al)(Si,Al)2O6
Sodium pyroxene series
Jadeite - NaAlSi2O6
Aegirine (Acmite) - NaFe3+Si2O6
Spodumene - LiAlSi2O6

36. Double chain inosilicates Double Chain – AMPHIBOLE GROUP
Two adjacent chains sharing O atoms.
Every other tetrahedron shares an O with the adjacent chains tetrahedron.

37. Double chain inosilicates
Amphibole group
Anthophyllite - (Mg,Fe)7Si8O22(OH)2
Hornblende - (Ca,Na)23(Mg,Fe,Al)5Si6(Al,Si)2O22(OH)2
Sodium amphibole group
Glaucophane - Na2Mg3Al2Si8O22(OH)2
Riebeckite (asbestos) - Na2Fe2+3Fe3+2Si8O22(OH)2
Arfvedsonite - Na3(Fe,Mg)4FeSi8O22(OH)2

38. Cyclosilicates 3-member ring 4-member ring 6-member ring
Benitoite - BaTi(Si3O9)
4-member ring
Axinite - (Ca,Fe,Mn)3Al2(BO3)(Si4O12)(OH)
6-member ring
Beryl/Emerald - Be3Al2(Si6O18)
Cordierite - (Mg,Fe)2Al3(Si5AlO18)
Tourmaline - (Na,Ca)(Al,Li,Mg)3-(Al,Fe,Mn)6(Si6O18)(BO3)3(OH)4

39. Phyllosilicates Sheet Silicates – MICA GROUP
Each tetrahedron share three O atoms to form a sheet.
+ ions that hold sheets together are sandwiched between silicate sheets.

40. Phyllosilicates Sheet Silicates – MICA GROUP
Serpentine group
Antigorite - Mg3Si2O5(OH)4
Chrysotile - Mg3Si2O5(OH)4
Clay mineral group
Kaolinite - Al2Si2O5(OH)4
Talc - Mg3Si4O10(OH)2
Mica group
Biotite - K(Mg,Fe)3(AlSi3O10)(OH)2
Muscovite - KAl2(AlSi3O10)(OH)2
Chlorite group
Chlorite - (Mg,Fe)3(Si,Al)4O10(OH)2•(Mg,Fe)3(OH)6

41. Tectosilicates Framework Silicates – Quartz Group
Tectosilicates, or "framework silicates," have a three-dimensional framework of silicate tetrahedra with SiO2 or a 1:2 ratio.
All four O ions are shared by adjacent tetrahedrons.

42. Tectosilicates
Tectosilicates, with the exception of the quartz group, are aluminosilicates.
Quartz and feldspar silicates are more complex b/c Al substitutes for some of the silicon in some of the tetrahedrons.

43. Examples Quartz group Feldspar group Quartz - SiO2 Tridymite - SiO2
Alkali-feldspars
Potassium-feldspars
Microcline - KAlSi3O8
Orthoclase - KAlSi3O8
Plagioclase feldspars
Albite - NaAlSi3O8
Oligoclase - (Na,Ca)(Si,Al)4O8 (Na:Ca 4:1)

44. BONUS POINTS
3-D models of silicate structures made with cardboard up to 5 bonus points!

45. Q! Explain the importance of the Silicon Oxygen Tetrahedron.
A! They are the building block for most common minerals on earth.

46. Non - Silicate Not abundant in earth DO not contain Silica
Still important

47. Non-silicate Minerals
Halides
-Contains chlorine, bromine, fluorine, and iodine are combined with one or more metals
Carbonates
Contain CO3 in their structures (e.g., calcite - CaCO3)
Sulfates
Contain SO4 in their structures (e.g., gypsum - CaSO4. 2H2O)
Sulfides
Contain S (but no O) in their structures (e.g., pyrite - FeS2)
Oxides
Contain O, but not bonded to Si, C or S (e.g., hematite - Fe2O3)
Native elements
Composed entirely of one element (e.g., diamond - C; gold - Au)

48. Halides
The minerals that make up the halide class form as evaporates – in environments that have chemicals dissolved in solution that evaporates and leave the minerals (precipitates) behind.
Minerals of the halide class all have: relative low hardness
moderate to high melting points
poor conductors of heat and electricity

49. Carbonates
In nature, carbon atoms join with oxygen to form the carbonate ion, CO3.
These ions combine with metal cations to form carbonate minerals.
The carbonates fall into three groups: the calcite group, the dolomite group and the aragonite group. The copper carbonate minerals azurite and malichite are the only important economic carbonates.

50. Carbonates
Calcite (CaCO3)

51. Sulfates The basic unit of the sulfate minerals are the SO4 groups.
These groups combine with metals to form the sulfate minerals.
A large number of minerals belong to this class, but only a few of them are common.
The class can be divided into the anhydrous (no water) sulfates and the hydrous (water) and basic sulfates.

52. Sulfates
Gypsum (CaSO4 (+2H2O))

53. Describe the importance of the non-silicate minerals.

54. Sulfides
The minerals that make up the sulfide class are composed of metal cations (+2 charge) combined with sulfur.
The sulfides form an important class of minerals which includes the majority of the ore minerals.
They form in environments low in oxygen.

55. Sulfides
Pyrite (FeS2)

56. Oxides
The minerals that make up the oxide class include those in which oxygen is combined with one or more metals.
Within the oxide class are several minerals of great economic importance. These include the chief ores of iron, chromium, manganese, tin, and aluminum.

57. Oxide examples
Hematite (Fe2O3)
Magnetite is another type of oxide!

58. Native Elements
Minerals that are composed of atoms of a single element are referred to as native elements.
Gold group
Platinum group
iron group
Semimetals group

59. Non- Silicate Minerals
Ore minerals
Minerals of commercial value
Most are non-silicates (primary source of metals)
Examples: magnetite and hematite (iron), chalcopyrite (copper), galena (lead), sphalerite (zinc)
Must be able to be extracted profitably to be considered current resources
Gemstones
Prized for their beauty
and (often) hardness
May be commercially useful
Diamond, corundum, garnet, and
quartz are used as abrasives

60. Variations in Mineral Structure and Composition
Only a limited # of minerals compositions exist
- Random combinations don’t happen
Combinations can only form a limited # of crystalline structures
Each type of mineral may NOT be compositionally different BUT
each type can show different structural variation

61. FOR EXAMPLE
Fe and Mg can interchange to create a range of compositions in Olivine (Fe,Mg)2 SiO4
Pure Mg olivine Mg2SiO4 forms bright green peridot
Pure Fe olivine Fe2SiO4 forms jet black fayalite
Crystal structures are identical

62. Olivine Variations
Fe2SiO4 Fayalite Mg2SiO4 Peridot

63. POLYMORPHISM
The same chemical composition but different crystalline structures
Calcite and Aragonite are both CaCO3 but crystal structures differ b/c of the environment where conditions and processes of formation differ

64. CaCO3
CALCITE
Aragonite

65. Properties Quiz What is STREAK and how is it used? What is LUSTER?
Is mineral color a reliable property for Identification?
What is the arrangement and formula for the silicon oxygen tetrahedron?
What is silica and Why is silica so important?

66. Mineral Properties
Physical and chemical properties of minerals are closely
linked to their atomic structures and compositions
Color
Visible hue of a mineral
Streak
Color left behind when mineral is scraped on unglazed porcelain
Luster
Manner in which light reflects off surface of a mineral
Hardness
Scratch-resistance
Crystal form
External geometric form

67. Mineral Properties Cleavage Fracture Specific gravity Magnetism
Breakage along flat planes
Fracture
Irregular breakage
Specific gravity
Density relative to that of water
Magnetism
Attracted to magnet
Chemical reaction
Calcite fizzes in dilute HCl