Review Unit 2A

Minerals and Rocks

#1. What are the four characteristics of a mineral?

Natural

Crystal

Inorganic

Solid

#2. The property that is MOST useful in identifying the unknown rock is Mineral content.

#3. Graphite is a mineral.

#4. Cleavage of a mineral is related to a mineral's crystalline structure

#5. Rocks found on Earth are generally classified by how the rocks are formed.

#6. The three main types of rocks?

Igneous

Metamorphic

Sedimentary

#7. Igneous rock is formed by volcanic activity, cooled and hardened magma and lava.

#8. Magma that cools and hardens forms an intrusive igneous rock. This is inside the Earth. Lava that cools and hardens forms an extrusive igneous rock. This is on the Earth’s surface.

#9. Metamorphic rocks form from heat and pressure. One source of this pressure is the mass of overlaying rocks.

#10. Sedimentary rocks form after rock has been weathered and erosion has moved the small rock particles. Sedimentary rocks are formed by cementation and compaction.

#11. It takes a long time for a rock to change from one type to another through the Rock Cycle.

#12. When limestone is exposed to enough heat and pressure, it goes through physical changes. These changes can turn limestone into a different kind of rock called marble. Marble is a metamorphic rock.

#13. The formation of metamorphic rocks depends on the composition of the parent rocks, temperature, and pressure.

#14. Sandstone is an example of a sedimentary rock.

#15. Studying fossils can show us how Earth's environments have changed.

#16. To find the absolute age of the fossil shells, the geologist would use radioactive isotopes

#17. In layers of sedimentary rocks the oldest fossils are found in the bottom layer. Younger fossils are found in the upper layers.

#18. Fossils of marine plants and animals were found high above sea level on a mountain. Explain how this can happen. The area was once sediment under the ocean. The mountains were pushed up after the marine life and plants died.

#19. For a fossil to form the entire plant or animal must be covered quickly. Mudslides, avalanches, and volcanic explosion are examples of events that can cause a fossil to be buried quickly then become a fossil over a long period of time.