1. Unit II Rocks and Minerals
Make sure that you copy down all the red information into your note packet.

2. A. Minerals
that have a definite chemical composition and molecular structure.
-classified on the basis of their
Their
and their
Naturally occurring, solid, inorganic substances
Physical and chemical properties
Chemical composition
Structure

3. Identification Don’t rely on color only to identify minerals
1. color- many minerals are found in a variety of colors.
- many minerals have the same color.
2. _________- color of a mineral in its powdered form.
-more reliable than color.
3. _________- the way in which light is refracted from the surface of a mineral.
a._______________- shine like polished metals.
b._______________- no metallic shine.
-glossy, pearly, greasy, dull, earthy, etc.
Quartz
Streak
Luster
Metallic
Nonmetallic
FYI - Metallic minerals usually have dark colored streaks.

4. Identification 1Talc 2Gypsum 3Calcite 4Fluorite 5Apatite 6Feldspar
4. Hardness- the resistance of a mineral to being
is used.
- glass has a hardness of 5.5.
scratched
Moh’s Scale
Softest
Hardest
Fingernail 2.5
1Talc
2Gypsum
3Calcite
4Fluorite
5Apatite
6Feldspar
7Quartz
8Topaz
9Corundum
10Diamond
Steel knife (nail) 5

5. Mica – 1 direction, sheets, Halite – 3 directions, cubic
Identification
5. ___________- the tendency of a mineral to split along one or more smooth, flat surfaces, or planes.
6. ___________- minerals that don’t have cleavage fracture when they break.
7. others- magnetism, may react with acid, double refraction (look through it and see double), taste, etc.
Cleavage
Mica – 1 direction, sheets, Halite – 3 directions, cubic
Fracture
Quartz, Magnetite, Garnet
Internal arrangement of atoms determines if there is cleavage or fracture.

6. Composition of the Earth’s Crust
Two most abundant elements
Make up a family of minerals known as the Silicates

8. Choose the minerals from the silicate family

9. Internal Arrangement of Atoms
The arrangment of the tetrahedral units controls: Breakage Hardness Crystal Shape

10. Rocks composed of one or more - there are over different minerals.
% of all rocks are composed of ten to fifteen different minerals called rock-forming minerals.
minerals
3,000 90

11. Igneous Rocks - form as a result of
____________- molten rock beneath the Earth’s surface.
____________- molten rock that has reached the Earth’s surface.
-most igneous rocks are (made of one or more minerals).
- when molten rock solidifies, it crystallizes into igneous rock.
- the crystals are made of different minerals.
solidification of molten (melted) rock
Magma
Lava
polymineralic

12. Igneous Rocks a. texture- the grain appearance.
-depends on the of the crystals and their arrangement within the rock.
- cooling time- affects the size of the crystals.
- long cooling time ____________ crystals.
- short cooling time ____________ crystals.
-very quick cooling- no grains form- rocks have a glassy texture obsidian.
size
large
small
- crystal shape – result of internal arrangement of atoms

13. Igneous Rocks questions: Where would rocks cool slowly vs. quickly?
Where would a rock with large crystals have been made?
Where would a rock with small crystals have been made?
Deep in earth’s crust where pressure and temperature are great. Called Intrusive Igneous Rocks
At or near the earth’s surface (volcanoes). Called Extrusive Igneous Rocks
Formed deep in the earth’s crust. Example – Granite
Formed at or near the earth’s surface. Example – Basalt

14. Using the Igneous Rock Chart
Can you find these on the chart?
Extrusive
Intrusive
General Characteristics
Textures
Mineral Names
Rock Names

15. Mineral Composition Coarse Granite
You need to be able to identify the minerals in the rock to use this section of the chart.
Big grain size, so the texture is?
Based on this information the rock name is?
Coarse
Granite

16. Finding the Rock Name Using Mineral Percents
Estimate the percent of each mineral in the rock (± 5%)
Plagioclase Feldspar
Pyroxene
Olivine
Amphibole
30%
60% 5%
The red line represents the mineral composition of the rock. 5%
The total must equal 100%

17. Try This One Peridotite Mineral Percents 25% Pyroxene 75% Olivine
Coarse Texture
Rock Name is
Peridotite

18. Andesite Try This One Mineral Percents 25% Amphibole 15% Biotite
60% Plagioclase
Fine Texture
(nonvesicular)
Andesite
Rock Name is

19. Sedimentary Rocks
most form as a result of of broken rock material. These broken pieces of rocks or sediments are usually deposited in large As they tumble down the streams and rivers that carry them, they tend to become
some form from chemical or biological processes.
compression and cementation
bodies of water (lakes and oceans)
rounded

20. Sedimentary Rocks All Clastic Sedimentary rocks form this way.
a. compression
pressure created by and overlying can be great enough to force particles of sediment close together, drive out any water present, and compact the sediments into a rock.
__________- forms from tiny particles of clay
water
sediments
Shale
All Clastic Sedimentary rocks form this way.

21. Sedimentary Rocks
b. _______________
when minerals such as silica, lime or iron oxide are added to sediments it tends to “glue” them together.
often gives the rock their color
Sedimentary rocks often show layering due to deposition on water. Sediments are sorted by size, shape, and density as they settle to the bottom
Cementation
Gray or white from silica or calcite (lime).
Red, brown or rust-colored from iron oxide

22. Sedimentary Rocks c. chemical processes -
- As water holding dissolved ionic minerals evaporates, it can’t hold all the minerals and they precipitate (fall out) of the water. Forms rocks with a mass of intergrown crystals.
- evaporites-
Formed by the evaporation and precipitation of sea water.
Also called Crystalline Sedimentary rocks
Rock salt – left behind after evaporation of ocean water.

23. Sedimentary Rocks Fossil and Rock Formation
d. biological processes
- rocks formed from
_______________- compression of dead plant materials
_______________- compressed and cemented corals and shellfish
e.__________- remains or impressions of plants and animals found in rocks.
- usually found in
once living things (organic matter)
coal
limestone
Called bioclastic sedimentary rocks
fossils
all different kinds of sedimentary rock.

24. Sedimentary Rocks Look for the following: Layers of sediments.
Pieces of other rocks cemented together.
Evidence of fossils
Sandstone
Conglomerate
Shale with Trilobite

25. Sed. Rock Groups Clasitic (fragmental) Look for visible sediments
Particles usually rounded
Sorted by size of sediments
Include: conglomerate, sandstone, shale

26. Sed. Rock Groups Crystalline (evaporites)
Rocks formed from evaporating sea water
Chemicals combine and settle to bottom of the ocean
Usually monominerallic
Include limestone, rock salt and rock gypsum .

27. Sed. Rock Groups Bioclastic (Organic) Formed from once living material
Usually contain a lot of fossils
Include limestone and coal
Fossil limestone
Coquina

28. Sedimentary Rocks and The Rock Cycle
Compression and Cementation
The blue and green arrows show what happens to sedimentary rocks.

29. Very Important Information
Reference Table Chart
3 Major Groups
Very Important Information

30. Metamorphic Rocks - classified according to their
- form as a result of the recrystallization of __________ rocks.
- occurs under conditions of extreme over long periods of time.
texture, grain size and composition.
Also if they exhibit banding or foliation.
unmelted
heat and pressure
- pressure increases the density of the rock, usually makes it harder to weather.

31. Metamorphic Rocks recrystallization- process in which rocks
- as a result of heat and pressure minerals in rocks combine to form new, crystalline structures.
- crystals often form in the rocks (gneiss)
- marble and quartzite have crystals larger than the crystals in the original rock they came from
undergo change without melting.
larger, denser, distorted
layer-like bands (banding)

32. Metamorphic Rocks
contact metamorphism- when molten rock comes in contact with existing rock, heat causes recrystallization of the rock materials and changes them into a new rock.

33. Regional Metamorphism
Example of Regional metamorphism
Occurs during mountain building and movements of the crust. Deeply buried rocks are subjected to high heat and pressure. Hot liquids and gases in the deep rocks can speed up the process.

34. Metamorphic Rock Chart
Two main groups.
Foliated
Nonfoliated

35. Main Characteristics Gneiss Look for bands of different color crystals
Look for distorted bands of crystals.

36. Main Characteristics Marble Quartzite More crystalline More Dense
Bigger crystals
Deformed bands
Distorted crystals

37. Using The Metamorphic Rock Chart
Three obs. Classify these rocks
Grain size
Composition
Texture
You’ll find a lot of information here.

38. Rock Samples: Foliated

39. Rock Samples:Nonfoliated
More crystalline

40. Is this rock foliated or nonfoliated?
Marble
What is this rock called?_____________________

41. Is this rock foliated or nonfoliated?
Gneiss
What is this rock called?_____________________

42. Rock Cycle Diagram