Earth Science Regents Review Unit 2

1) What are the five characteristics of a mineral? Must be naturally occuring Inorganic Solid Definite chemical composition Definite crystal structure

2) What controls the physical properties of a mineral? The internal arrangement of the atoms.

3) What are the five property tests for mineral identification? A) color: least reliable; many minerals share the same color or a mineral may come in many colors.

B) Luster: the way it shines; nonmetallic or metallic

C) Streak: the color of the powder after rubbing on a streak plate (true color)

D) Hardness: the resistance to being scratched.

E) Cleavage or fracture: how it breaks (cleavage=sharp flat surfaces; fracture= jagged edges)

1) What is an igneous rock? A rock formed from molten lava or magma.

3) Where can igneous rocks form? (a) Deep inside the earth= intrusive (b) At or close to the surface= extrusive

5) How can we tell how fast or slowly the igneous rock has cooled? (a) Slow cooling= large crystals (b) Fast cooling= small or no crystals

8) What is a vesicular texture and how does it form? It is a texture with gas pockets that form when gases escape.

10) What are felsic rocks? Mafic? Felsic rocks are light colored with low density. Mafic rocks are dark colored with high density.

11) What features do igneous rocks have? Igneous rocks have intergrown crystals of different colors, glassy feature and vesicles.

1) What is a sedimentary rock? Rocks that form from an accumulation of sediments.

3) Where do most sedimentary rocks form? Large bodies of water.

4) What are the four methods of formation? Cementation Compaction Chemical action Biologic processes

5) What is the process of cementation? Sediments lose water and the dissolved minerals in the pores precipitate out forming crystals.

8) How do chemical sedimentary rocks form? Dissolved minerals drop out from water when it evaporates.

9) Are chemically formed sedimentary rocks monominerallic or polyminerallic?

13) What are the four features of a sedimentary rock? Layers Fossils Fragments stuck together Crystals all one color

2) How does metamorphism occur? A rock is changed through intense heat or intense pressure or both.

4) What are some characteristics of rocks that have undergone recrystallization? (a) Mineral alignment: minerals are squeezed and forced to line up (b) Banding: alternating light and dark layers; “zebra stripes” (c) Crystal grains that can’t be separated, i.e. sandstone into quartzite

5) What are the two types of metamorphism? (a) Regional: intense pressure and some heat from mountain building (b) Contact: intense heat from magma touching cold surrounding rocks

7) What are the two classifications of metamorphic rocks? (a) Foliated: looks like layers in the rock caused by mineral alignment (b) Nonfoliated: no layers but is a hard dense crystalline mass

8) Where are metamorphic rocks found? Metamorphic rocks are found in between igneous and sedimentary rocks

9) What are the features of metamorphic rocks? Banding (looks like zebra stripes) Mineral alignment (looks like sparkly layers) Hard, dense crystalline mass Distorted structure (stretched out)