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Earth Science Journal!
Title: Rock Identification
This journal entry is very self-guided. Feel free to copy some of the images that you feel are important to another document and resize them to color and cut them out to include in your journal.
Please take out your reference tables and take notes on how to identify Igneous, Sedimentary, and Metamorphic rocks.
Be sure to watch the following videos carefully. They will help immensely with your next lab and Regents Performance Test!
Igneous Rock Identification
Sedimentary Rock Identification
Metamorphic Rock Identification
Notes1. What is Rock? Rocks are mixtures of minerals, glass, and/or organic matter.
2. Mono-mineralic rocks: rocks made from one mineral.
This is Fossil LimestoneIt is considered bioclastic (fragments of stuff that once was alive)
3. Poly-mineralic rocks: rocks made from more than one mineral.
This is GraniteScattered, intergrown crystals (1-10 mm in size) containing quartz and feldspar
4. How are Rocks Classified? Rocks are classified by how they form and their composition.
5. Igneous Rocks: melting and solidification of magma or lava
6. Sedimentary Rocks: Sediments cemented and compacted together
7. Metamorphic Rocks: Rocks changed by heat and pressure (not melted).
8. What is the Rock Cycle? It shows how rocks are formed
Color this rock cycle diagram and include it in your journals.
Make sure that you can still read the words.
9. What are the two steps to form igneous rock? (Color-Red
1. Melting 2. Solidification
10. What are the two steps to form a Metamorphic Rock? (Color-Purple)
1. Heat + Pressure 2. Metamorphism
11. What are the seven steps to form a sedimentary rock? (Color-Blue)
1. Uplift 2. Weathering 3. Erosion 4. Deposition 5. Burial 6. Compaction 7. Cementation
12. Any rock can make any other rock, including itself.
Note: Only a few minerals are needed to produce 90% of the earth's rocks. Common rock-forming minerals include Quartz, Feldspar, Hornblende, Mica
Different types of magma become different types of igneous rocks.
13. Mafic magma: dense, dark, no quartz (Mellow shield volcanoes)
Mauna Loa, Hawaii
14. Felsic Magma: low density, light-colored, high quartz, (Violent Strato Volcanoes)
Mount Fuji, Japan
15. Which igneous rock is more (dense, mafic, dark) Granite or Gabbro? Gabbro, Gabbro is farther to the right in the diagram making it more mafic and made up of darker minerals.
Intrusive and Extrusive igneous rocks16. Intrusive igneous rocks (Plutonic): slow cooling of magma. Minerals have a long time to grow, making large, inter-grown crystals.Examples: granite, diorite, gabbro
Granite
DioriteSometimes, igneous rocks have larger crystals embedded in a fine-grained matrix.(Porphyritic)
17. Extrusive igneous rocks (Volcanic): formed by quick-cooling lava. When igneous rocks cool quickly, crystals have a short time to grow to make them very small, vesicular, or glassy in texture.Examples: obsidian, basalt, rhyolite, and pumice.
Sometimes, they cool so fast that they turn to glass or trap gasses, making their texture vesicular.
Vesicular = Gas Pockets
Pumice
Draw the following examples.
Drawn to scale
18. Are these rock samples intrusive or extrusive?
How do you know?They are intrusive because they have coarse texture (large crystals).
Therefore, they cooled slowly inside the earth.19. Which rock cooled the slowest? B Fastest? C
20. How do you know? The bigger crystals had more time to grow (cooled slower)
21. What is the name of a coarse-grained igneous rock that contains potassium feldspar? Granite
Scroll over the image to see the answer.
22. What is the name of a glassy vesicular mafic igneous rock made mostly of pyroxene? Scoria
Scroll over the image for the answer.
23. This felsic volcanic rock cooled so fast that it turned to glass. Obsidian
24. Sedimentary Rocks are classified by texture and composition.
25. Clastic Texture: Worn-away fragments from older rocks.
Clastic Sedimentary Rocks are classified based on the grain size of the sediment.
Sediment: loose material of rock, gravel, sand, silt, mud, plant and animal remains eroded by wind or water (transported). Sediments also can come out of solution (precipitate) and settle at the bottom of a body of water as the water evaporates away.
26. Sediments are turned to rock through:
Compaction: squeezing out water, till the particles stick
Cementation: Water deposits natural cement, cementing the particles together.
Conglomerate
Breccia
Sandstone
27. Crystalline Texture: minerals crystallize out of solution as water evaporates.
28. Bioclastic Texture: Made from remains of living things (fossil-rich).
Limestone will fizz when HCL acid is applied.
Examples: limestone - made from fossil shells; Coal - dead plant material.
Reference Tables: Scheme for Sedimentary Rocks
29. Metamorphic Rocks are classified by composition and texture.
30. Foliated Texture: Flattened mineral grains, lined up in parallel bands
Examples: slate, gneiss (mineral banding).
Gneiss
CAUTION!!! Do not confuse these with sedimentary rocks!
These mineral bands are NOT layers of sediment!
31. Non-foliated Texture: Mineral grains not arranged in layers or bands.
Examples: Quartzite (from sandstone), Marble (from limestone)
Quartzite
Marble
What tests could you do to tell the difference between Marble and Quartzite?
If it scratches glass it is quartzite, if it fizzes in acid it is marble.
Print out and include this image in your journal.
32. Sandstone becomes Quartzite under intense heat and pressure.33. Limestone becomes Marble under intense heat and pressure.34. Conglomerate becomes Metaconglomerate under intense heat and pressure.35. Shale becomes Slate under intense heat and pressure.
Identify these rocks.
A = Gneiss B = Shale C = Obsidian D = Granite E = Conglomerate 
What are rocks A-G
A = Limestone
B = Shale
C= Sandstone
D = Folded rock layers (no symbol given for type of rock)
E = Igneous Intrusion (probably basalt)
F = Marble
G = Quartzite
Please write the following questions and answers in your journal.
Answer these questions for review. These are very typical regents questions.1. According to the Scheme for Sedimentary Rock Identification, which characteristic determines whether a rock is classified as shale, siltstone, sandstone, or conglomerate?
1. the absolute age of the sediments within the rock
2. the mineral composition of the sediments within the rock
3. the particle size of the sediments within the rock Correct Answer!
4. the density of the sediments within the rock2. The recrystallization of unmelted material under high temperature and pressure results in
1. metamorphic rock Correct Answer!
2. sedimentary rock
3. igneous rock
4. volcanic rock3. A rock with a distorted layer structure is most likely the result of
1. a long period of weathering
2. glacial activity
3. wind erosion
4. extreme pressure Correct Answer!
4. An igneous rock contains large mineral crystals. The best conclusion to make about this rock is that it
1. contains plagioclase and pyroxene
2. is felsic and has a low density
3. once contained small crystals which eroded
4. cooled slowly as it formed Correct Answer!
5. Base your answer to the question on the "Properties of Common Minerals" chart in the Earth Science Reference Tables. Minerals from this chart are found in several different rocks. Which two rocks are primarily composed of a mineral that bubbles with acid?
1. limestone and marble Correct Answer!
2. granite and dolostone
3. sandstone and quartzite
4. slate and conglomerate6. Rhyolite is an example of a
1. monomineralic igneous rock
2. polymineralic igneous rock Correct Answer!
3. monomineralic sedimentary rock
4. polymineralic sedimentary rock7. Which rock was most likely formed from pebble-sized sediment deposited in shallow water at an ocean shoreline?
1. shale
2. basalt
3. siltstone
4. conglomerate Correct Answer!
8. Some nonsedimentary rocks are formed as a result of
1. solidification of molten material Correct Answer!
2. evaporation and precipitation
3. cementation of particles
4. deposition of particles9. Where is metamorphic rock frequently found
1. on mountaintops that have horizontal layers containing marine fossils
2. within large lava flows
3. as a thin surface layer covering huge areas of the continents
4. along the interface between igneous intrusions and sedimentary rocks Correct Answer!
10. Which is an accurate statement about rocks?
1. Rocks are located only in continental areas of the Earth.
2. Rocks seldom undergo change.
3. Most rocks contain fossils.
4. Most rocks have several minerals in common. Correct Answerr!Highlight the above questions for the correct answers.
Write down the following.
Reflection: Explain the difference between igneous, sedimentary, and metamorphic rocks.BonusMake a small rock identification box with the following rocks that you should find on the shore of Lake Ontario.Find, label, and identify the following.One sedimentary rock shows either layers of sediment or fossils (shale, siltstone, sandstone)One metamorphic rock showing mineral alignment or banding (schist, or gneiss)One igneous rock showing scattered intergrown crystals (granite, diorite, or gabbro)Make the samples no bigger than 5 inches in diameter.
