1. Chapter 2
Minerals

3. 2.2 Minerals Definition of a Mineral
1. D-Definite chemical composition
2. I-Inorganic (not containing both carbon & hydrogen)
3. N-Naturally occurring
4. C-Crystalline structure (atoms are arranged orderly & repetitively)
5. S-Solid substance
Crystals

4. 2.2 How do Minerals Form?
Minerals form nearly everywhere on Earth under different conditions
There are FOUR major processes by which minerals form
Crystallization from magma
Precipitation
Changes in pressure & temperature
Hydrothermal solutions

5. 2.2 Crystallization
Crystallization - Minerals in molten rock crystallize as the rock cools
muscovite
feldspar
quartz
hornblende

6. Precipitation
2. Precipitation—dissolved substances in water can form minerals as the water evaporates
limestone
halite

7. 2.2 Pressure & Temperature
3. Pressure and temperature —existing minerals can create new minerals by rearranging the crystalline structure
Ex: talc

8. 2.2 Hydrothermal Solutions
4. Hydrothermal solutions—mixture of hot water and dissolved substances form new minerals through chemical reactions when they mix with existing minerals or when the mixture cools

9. 2.2 Minerals Mineral Groups
 Can be classified based on their composition
1. Silicates
Silicon and oxygen combine to form a structure called the silicon-oxygen tetrahedron. This silicon-oxygen tetrahedron provides the framework of every silicate mineral.
Most abundant mineral group—75% crust

10. The Silicon-Oxygen Tetrahedron
1 Silicon atom
4 Oxygen atoms

11. Silicon-Oxygen Chains, Sheets, and Three-Dimensional Networks

12. 2.2 Minerals Mineral Groups 2. Carbonates 3. Oxides
Minerals that contain the elements carbon, oxygen, and one or more other metallic elements
Ex: Limestone, marble
3. Oxides
Minerals that contain oxygen and one or more other elements, which are usually metals

13. Carbonates
Calcite
Dolomite

14. Oxides
Corundum
Hematite

15. 2.2 Minerals Mineral Groups 4. Sulfates and Sulfides 5. Halides
Minerals that contain the element sulfur
Ex: pyrite (fool’s gold)
5. Halides
Minerals that contain a halogen ion plus one or more other elements Ex: Salt (halite)
6. Native elements
Minerals that exist in relatively pure form
Ex: Gold, Silver, Copper, Sulfur, Diamond, Graphite

16. Sulfides
Galena
Pyrite

17. Halides
Fluorite
Halite

18. Native Elements
Copper
Gold

19. 2.3 Properties of Minerals
Minerals are classified by their physical properties
Color
Small amounts of different elements can give the same mineral different colors.
Different minerals can have the same color
Least reliable property

20. QUARTZ

21. Corundum Vanadinita Realgar Cinnabar Beryl
Red corundum is a ruby. Blue corundum is a sapphire. Green Beryl is an emerald

22. 2.3 Properties of Minerals
Streak
 Streak is the color of a mineral in its powdered form.

23. 2.3 Properties of Minerals
Luster
2.3 Properties of Minerals
Luster is used to describe how light is reflected from the surface of a mineral.
Metallic
Nonmetallic

25. 2.3 Properties of Minerals
Crystal Form
2.3 Properties of Minerals
Crystal form is the shape the crystals tend to take as they grow (structure)
If it forms slowly, it will have well-formed faces (sides, top, bottom)
If it forms fast, minerals compete for space
Crystal
Growth

27. Quartz Often Exhibits Good Crystal Form.

28. 2.3 Properties of Minerals
Hardness
2.3 Properties of Minerals
 Hardness is a measure of the resistance of a mineral to scratching and abrasion.
 Mohs scale consists of minerals arranged from 10 (hardest) to 1 (softest).

29. Mohs Scale of Hardness

30. 2.3 Properties of Minerals
Cleavage
2.3 Properties of Minerals
 Cleavage is the tendency of a mineral to cleave, or break, along flat, even surfaces.

33. Mica Has Cleavage in One Direction

34. 2.3 Properties of Minerals
Fracture
2.3 Properties of Minerals
 Minerals that do not show cleavage when broken are said to fracture.
 Fracture—the uneven breakage of a mineral

35. Conchoidal Fracture

36. Splinter or Fiber Fracture
Asbestos

37. 2.3 Properties of Minerals
Density
2.3 Properties of Minerals
Density (Specific Gravity) is a property of all matter that is the ratio of an object’s mass to its volume.
Density = mass (m)
volume (V)
Density of a pure mineral is a constant value
Density can be used to determine the purity or identity of some minerals

38. 2.3 Properties of Minerals
Distinctive Properties of Minerals
Some minerals can be recognized by other distinctive properties.
Magnetism
Effervescence—”bubbles”
Fluorescence—glow under some conditions
Taste—salty, sweet, etc.
Touch—greasy, soapy, etc.
Smell—rotten eggs, etc.

39. 2.3 Fluorescent Minerals Scheelite
Calcite with Zincite and Willemite Inclusions
Hardystonite with Willemite, Franklinite, and Calcite
Scheelite

40. 2.3 Mineral Resources Where do minerals come from?
Resource—the total amount of a mineral material in the Earth
Renewable—a mineral resource that is made faster than it is used
Non-renewable—a mineral resource that is used faster than it gets made

41. 2.3 Mineral Resources Where do minerals come from?
Reserve—the portion of the mineral substance that has been identified
Ore—a mineral resource that can be mined profitably

42. 2.3 Mineral Uses
Agriculture - fertilizers (superphosphate, limestone, dolomite)
Automotive industries - steel, high temperature ceramics (spark plugs, cylinder heads), sulphur (used in vulcanising of rubber), lead and antimony (batteries) etc.
Building materials - cement (from calcite), bricks (from clay and shale), glass (from quartz sand), plaster (from gypsum)
Chemical industries - manufacture of paints, paper, ceramics, glass
Cooking (salt, baking powder)
Currency - coins (copper, bronze, nickel, silver, gold)
Electronics, copper electrical wiring, computers, space industry - gold, silver, copper, silicon, uncommon metals (gallium, tantalum, tungsten), special glasses and ceramics
Jewelry and decorative items (gemstones, gold, silver, platinum)
Metallurgy and metal smelting - iron, steel, copper, bronze, brass, lead, zinc, gold, silver, aluminium, special metal alloys etc.
Plumbing - copper, lead (in the past)
Surgery, medicines, pharmaceuticals, cosmetics (titanium, tantalum and stainless steel implants), dietary supplements (zinc and iron tablets), talcum powder (from talc)