1. Chapter 1 Minerals in the Earth’s Crust

2. SECTION 1

3. mineral
a naturally formed, inorganic solid that has a definite crystalline structure
Must be able to say “yes”
1. must be a solid
2. must be a nonliving material
3. must have a crystalline structure
4. must be formed in nature (not by man)

5. elements
pure substances that cannot be broken down into simpler substances by ordinary chemical means

6. compound
a substance made of two or more elements that have been chemically joined or bonded
NaCl = Sodium + Chlorine = salt
H2O = Hydrogen + Oxygen = water

7. native element a mineral composed of only one element
Example: gold and silver

8. General Facts about Minerals
Between 2 - 3,000 have been identified
A few are “native elements” -- made of only one element, such as sulfur, gold. copper, and graphite (carbon)
Most are compounds, especially the silicate group (Si, O).
Other important groups are oxides, carbonates, and sulfides.

9. Less than a dozen are common in most rocks
Olivine
Amphibole (group)
Magnetite, limonite, and other iron oxides
Pyrite
Quartz
Feldspar (group)
Muscovite (white mica)
Biotite (black mica)
Calcite
Pyroxene

10. Common uses include: Aluminum--packaging, transport, building
Beryllium--gemstones, fluorescent lights
Copper--electric cables, wires, switches
Feldspar--glass and ceramics
Iron--buildings, automobiles, magnets
Calcite--toothpaste, construction

11. crystals
solid, geometric forms of minerals produced by a definite repeating pattern of atoms that is resent throughout the mineral

12. silicate minerals
a mineral that contains a combination of silicon, oxygen and one or more metals
make up more than 90% of Earth’s crust
silicon and oxygen combine with other elements such as aluminum, iron, magnesium and potassium to make up silicate materials

13. Common Silicate Minerals
Feldspar
KAlSi3O8
Mica
Biotite
K(Mg, Fe)3AlSi3O10(F, OH)2
Quartz
Silicon Dioxide
SiO2

14. nonsilicate minerals
minerals that do not contain a combination of the elements silicon and oxygen
some made up of carbon, oxygen, fluorine and sulfur
native elements, oxides, carbonates, sulfates, halides & sulfides

15. Classes of Nonsilicate Minerals
Native Elements - composed of only one element.
Gold
Copper

16. Classes of Nonsilicate Minerals
Oxides - form when an element (such as aluminum or iron) combines chemically w/ oxygen.
Corundum
Al2O3
Aluminum oxide

17. Classes of Nonsilicate Minerals
Carbonates - contain combinations of carbon and oxygen in their chemical structure.
Calcite
CaCO3

18. Classes of Nonsilicate Minerals
Sulfates - contain sulfur and oxygen, SO4.
Gypsum
Calcium Sulfate Dihydrate
CaSO4·2H2O

19. Classes of Nonsilicate Minerals
Halides - form when:
flourine, chlorine, iodine, or bromine
combine with
sodium, potassium, or calcium
Flourite
Calcium Fluoride
CaF2

20. Classes of Nonsilicate Minerals
Sulfides - contain one or more elements (such as lead, iron, or nickel) combined with sulfur.
Galena
Lead Sulfide
PbS

21. SECTION 2

22. Minerals are identified by their key characteristics
hardness
crystal shape (form)
luster
color
streak
cleavage/fracture
density (specific gravity)
special properties --reaction to acid --fluorescence salty taste magnetism

23. COLOR
results from ability to absorb some wavelengths and reflect others
some minerals have characteristics colors
others vary due to chemical differences or impurities (atoms mixed inside the main elements)
because of factors such as impurities, color is not the best way to identify a mineral

24. COLOR

25. LUSTER Describes how light reflects off the surface
“shiny” = metallic luster
“dull” = submetallic or nonmetallic luster

26. STREAK
Color of the powder when rubbed on a “streak plate” (unglazed porcelain)
can be found by rubbing the mineral against a piece of unglazed porcelain
powdered color is not always the same color of the mineral sample

27. Streak Plate = a piece of unglazed porcelain used to test the streak of minerals

28. Submetallic - dull, reflective
Euxenite

29. Nonmetallic
Vitreous
glassy, brilliant
Pollucite

30. Nonmetallic
Silky
fibrous
Gypsum

31. Nonmetallic
Resinous
plastic
Sphalerite

32. Nonmetallic
Waxy
greasy, oily
Cancrinite

33. Nonmetallic
Pearly
creamy
Stellerite

34. Nonmetallic
Earthy
rough, dull
Kaolinite

35. Cleavage of mica
into thin sheets
Cleavage = the tendency of some minerals to break along smooth, flat surfaces

37. Cleavage in calcite

38. fracture in obsidian
fracture = the tendency of some minerals to break unevenly along curved or irregular surfaces

39. HARDNESS a mineral’s resistance to being scratched
the greater a mineral’s resistance to being scratched, the higher the rating
Mohs scale from 1 (talc) to 10 (diamond)
Quartz (most common mineral and most dust particles) is 7

40. MOHS HARDNESS SCALE

41. DENSITY (Specific Gravity)
All minerals have density (mass / volume), but some are very dense
Examples include galena, magnetite, and gold
Specific Gravity is the density of the mineral compared with density of water

42. SPECIAL PROPERTIES
particular to only a few types of minerals – need specialized equipment to determine these properties
EXAMPLES: fluorescence, chemical reaction, optical properties, magnetism, taste, radioactivity

43. Special Property - Fluorescence
Some minerals will glow when placed under short-wave or long-wave ultraviolet rays
Franklin and Ogdensburg NJ are famous for their fluorescent minerals
Calcite (red) and willemite (green)

44. Special Property - Salty Taste
DO NOT TASTE MOST MINERALS!
Halite is the exception--it will taste salty
Borax tastes sweet.

45. Special Property - Magnetism
Many iron minerals will produce an invisible magnetic force field
“Lodestone” was used by Vikings more than 1,000 years ago as compasses

46. Special Property - Radioactivity
Autunite contains uranium.

47. Special Property - Chemical reaction carbonates react with dilute HCl and other acids by fizzing or bubbling (releasing CO2 gas)
CaCO3 + 2HCl = CO2 + H2O + CaCl2
calcite
hydrochloric acid

48. Special Property - Optical properties such as double refraction.
Same sample of calcite, but it’s rotated.

49. SECTION 3

50. Evaporating Salt Water
when a body of salt water dries up/evaporating these minerals crystallize
Examples = gypsum and halite

51. EVAPORATING SALT WATER

52. Limestones
surface water & groundwater carry dissolved materials into lakes & oceans where they crystallize on the bottom
Examples = calcite and dolomite

53. LIMESTONES

54. Metamorphic Rocks
when changes in pressure, temperature or chemical makeup alter a rock
Examples = calcite, garnet, graphite, hematite, magnetite, mica and talc

55. Hot-Water Solutions
Groundwater works its way downward and is heated by magma, then reacts with minerals to form a hot liquid solution. Dissolved metals and other elements crystallize to form new minerals.
Examples = gold, copper, sulfur pyrite and galena

56. Hot Water Solutions
This vein of gold was formed this way.

57. Plutons
when magma rises upward through the crust and stops before reaching the surface it cools slowly forming millions of mineral crystals – it eventually solidifies to form a pluton
Examples = mica, feldspar, magnetite and quartz

58. Pegmatites Magma moves upward and forms teardrop-shaped bodies
Examples = topaz, tourmaline
can grow to several meters across
Pictured here is a sample of tourmaline from a pegmatite.

59. ORE
a mineral deposit large enough and pure enough to be mined for profit
removed by two methods = surface or subsurface mining

60. SURFACE MINING
When mineral s deposits are located at or near the surface of the earth
kinds = open pits, surface coal mines and quarries
surface coal mining also called strip mining

61. OPEN PIT MINING
used to remove large, near-surface deposits of economically important minerals such as gold and copper

62. QUARRIES
open pits that are used to mine building stone, crushed rock, sand and gravel

63. SUBSURFACE MINING
when mineral deposits are located too deep within the earth’s to be surface mined
often requires passageways to be dug into the earth to reach the ore

64. RECLAMATION
the process of returning land to its original condition after mining is completed
required by law  
reduces the potential harmful effects of mining to return the land to its original state after mining is completed

65. METALLIC MINERALS
have shiny surfaces, do not let light pass through them and are good conductors of heat and electricity
can be processed into metals that are strong and do not rust, can be pounded into various shapes or stretched thinly without breaking

66. NONMETALLIC MINERALS
have shiny or dull surfaces, may let light pass through them and are good insulators of electricity
most widely used minerals in industry

67. GEMSTONES
nonmetallic minerals that are highly valued for their beauty and rarity rather than their usefulness
diamond, ruby, sapphire, emerald, aquamarine, topaz and tourmaline
color is the most important characteristic of a gemstone
must be durable and hard enough to be cut and polished

69. carat the unit used to express the mass of a gemstone
one carat = 200mg