Lec 4: Minerals and Rock Cycle

Question 1

Lecture’s goals:

1_ Define the term “mineral”

2_ Describe 4 major ways that minerals can form

3_ Describe how minerals are “categorized” into groups

4_ Use a mineral’s chemical formula to determine its group

5_ List and describe 3 main rock types

6_ Describe how each type of rock can change into another

Answer 1

Lecture’s goals:

1_ Define the term “mineral”

2_ Describe 4 major ways that minerals can form

3_ Describe how minerals are “categorized” into groups

4_ Use a mineral’s chemical formula to determine its group

5_ List and describe 3 main rock types

6_ Describe how each type of rock can change into another

Question 2

Lecture’s goals:

1_ Define the term “mineral” (note: include words that describe it)

Answer 2

Mineral is a structurally homogeneous solid of definite chemical composition, formed by the inorganic processes of nature

Words to describe minerals:
1_ naturally occurring
2_ inorganic
3_ solid
4_ crystalline structure (geometric arrangement of atoms)
5_ Consistent chemical composition
6_ Physical properties reflect composition and crystalline structure

Question 3

Lecture’s goals:

2_ Describe 4 major ways that minerals can form

Answer 3

1_ Cooling and crystallization from magma
( small crystals = cooled quickly, large crystals = cooled slowly)

2_ Precipitation from fluid (remnants of lake’s evaporation)

3_ Chemical changes from heat and pressure

4_ Precipitation from biogenic activity (biomineralization)

Question 4

Lecture’s goals:

3_ Describe how minerals are “categorized” into groups (or: How do we identify minerals?)

Answer 4

By (1) observable physical properties, and (2) other properties

Color; luster; streak; hardness; cleavage; fracture; and more

Question 5

Lecture’s goals:

4_ Use a mineral’s chemical formula to determine its group (3 chemical groups)

Answer 5

1_ Silicate minerals
-> Mafic: dark silicates
-> Felsic: light silicates

2_ Carbonate minerals: Calcite, hardness of 3

3_ Sulfide minerals

Question 6

Lecture’s goals:

5_ List and describe 3 main rock types

Answer 6

3 main rock types:
_ igneous: crystallize from a melt (magma)
_ metamorphic: formed from the alteration of pre-existing rocks
_ sedimentary: either grains or biological or chemical precipitation

Question 7

Lecture’s goals:

6_ Describe how each type of rock can change into another

Answer 7

Refer to the rock cycle graph. Description in words: Outcrop, through weathering, erosion, and deposition, turns into sediment, sediment is either buried, compacted, or cemented into sedimentary rocks(sediment is above the earth’s surface and sedimentary rock is below). Deeper burial and heat and pressure turn sedimentary rocks into metamorphic rocks. Metamorphic rocks melt into magma. Magna cools and becomes intrusive igneous rocks (if under the earth’s surface) or extrusive igneous rocks (if on the earth’s surface) Ex or in igneous rocks uplift into outcrop. Each type of rock can be buried or uplifted into 1 another.