1. Rocks and Minerals Ch. 1 and 2

2. Grouping minerals
How can you group the minerals your group has been given?
Think of how you group other things in nature:
Clouds
Trees
Birds
Buildings

3. What is a mineral? A naturally occurring inorganic solid
with a definite (but not fixed) chemical composition
and a highly ordered arrangement

4. Minerals are made from elements
Most common elements:
Oxygen
Silicon
Aluminum
Iron
Calcium
Magnesium
Sodium
Potassium
Percentage by Weight

5. Properties of Minerals
Crystal form
Habit
Cleavage
Hardness
Luster
Color
Streak
Density
Did you use any of these properties for grouping your minerals?

6. Crystal Form-
Internal arrangement of atoms determines outward appearance

7. Habit-shape of a mineral or group of minerals

8. Geode
Stalactitic
Botryoidal
Habit
Mammillary
Radiating
Fibrous

9. Cleavage-preferred plane of weakness
Do all minerals have cleavage?

10. Mohs Hardness Scale 3 4 5 1 2 9 10 6 7 8

11. Mohs Hardness Scale fingernail Copper penny glass Streak plate softest
1 - Talc
2 - Gypsum
3 - Calcite
4 - Fluorite
5 - Apatite
6 - Potassium Feldspar
7 - Quartz
8 - Topaz
9 - Corundum
10 -Diamond
fingernail
Copper penny
glass
Streak plate
hardest

12. Luster-how a mineral reflects light
Metallic metal like
Vitreous - glass like
Resinous - resin like
Pearly - pearl like
Greasy - slippery
Non Metallic

13. Luster
Metallic
Nonmetallic

14. Color-what is the usefulness of this attribute in identifying minerals?

15. Color of Streak

16. Density
box of feathers
box of hammers

17. Important crustal minerals
Feldspar group (plagioclase and orthoclase)
Quartz
Calcite and dolomite
Pyroxene group
Amphibole group (biotite and muscovite)
Olivine
Halite (salt)
gypsum

18. What is a rock?
An aggregate of one or more minerals

19. Groups of rocks Igneous Sedimentary Metamorphic
Characterized by how they form
Related by the rock cycle

20. Rock Cycle

21. Igneous rocks Crystallize from a molten rock: magma
Magma: liquid rock beneath earth’s surface
Lava: liquid rock above earth’s surface
Igneous rocks classified on
Mineral size
composition

22. Igneous rocks Intrusive igneous rocks Extrusive igneous rocks
Cool below ground (slowly)
All minerals visible w/out microscope
Extrusive igneous rocks
Cool above ground (fast)
Most minerals too small to see w/out microscope

23. Igneous rocks
Intrusive igneous rocks
Extrusive igneous rocks

24. Intrusive or extrusive?

25. Slow or fast cooling?

26. Intrusive or extrusive?

27. Slow or fast cooling?

28. Light colored igneous rocks
Granite and rhyolite

29. Intermediate igneous rocks
Andesite

30. Dark colored igneous rocks
Gabbro and basalt

31. Rock Cycle
Igneous rocks can become what other kind of rocks?

32. Sedimentary rocks
Clastic sed rock: made of solid particles once part of other rocks
Classified by grain size
Chemical sed rock: made from dissolved material in water
Classified by chemical composition
Biochemical sed rock: made of dead plants and animals

33. Biochemical, chemical, or detrital?

34. Clastic sed rocks Big particles Conglomerate Sand size Sandstone
Small particles Mudstone (shale)

35. Clastic sed rocks Conglomerate
Clue: Particles of lots of different sizes

36. Clastic sed rocks
Sandstone
Clue: feels sandy

37. Clastic sed rocks Mudstone (shale) Clue: very small particles
No grit when you taste it

38. Chemical sed rocks Limestone Made of calcite Clues: fizzes with acid
Often contains fossils

39. Chemical sed rocks Rock salt/halite Gypsum Clue: tastes salty
Clue: easily scratched, not salty

40. Biochemical sed rocks Category of chemical sed rocks Coal
Limestone if with fossils

41. Importance of sed rocks
Key to interpreting Earth’s history