ES 9A.STUDENTS KNOW THE RESOURCES OF MAJOR ECONOMIC IMPORTANCE IN CALIFORNIA

AND THEIR RELATION TO CALIFORNIA’S GEOLOGY.

Ch 5. Minerals

Characteristics of Minerals

To be a mineral, a substance must have four characteristics:

must be inorganic—it cannot be made of or by living things;

must occur naturally—it cannot be man-made;

must be a crystalline solid; must have a consistent chemical

composition.

Kinds of Minerals

All minerals can be classified into two main groups — based on their chemical compositions.

silicate mineral contains a combination of silicon and oxygen, may also contain one or more metals

Silicate minerals make up 96% of Earth’s crust.

nonsilicate mineral does not contain compounds of silicon and oxygen

Make up about 4% of Earth’s crust.

Physical Properties of Minerals

Coloris unreliable for the identification of minerals.can be affected by impurities or by weathering

processes.

Streakthe color of a mineral in powdered formdetermined by rubbing some of the mineral

against an unglazed ceramic tile called a streak plate.

Lusterthe way in which a mineral reflects light

metallic luster if it reflects light

All other minerals have nonmetallic luster.

Ex. glassy, waxy, pearly, brilliant, and earthy.

Cleavagethe tendency of a mineral to split along

specific planes of weakness to form smooth, flat surfaces

Fracturethe manner in which a mineral breaks along

either curved or irregular surfaces

Physical Properties of Minerals

Hardnessthe ability of a mineral to resist scratching

is called hardness.

Mohs hardness scale the standard scale against which the hardness of minerals is rated.

The strength of the bonds between the atoms that make up a mineral’s structure determines the hardness of a mineral.

STUDENTS KNOW HOW TO EXPLAIN THE PROPERTIES OF ROCKS BASED ON THE PHYSICAL

AND CHEMICAL CONDITIONS IN WHICH THEY FORMED, INCLUDING PLATE TECTONIC PROCESSES

Ch 6 ROCKS

Three Major Types of Rock

Rock: The material that makes up the solid parts of Earth.

Rocks are classified based on the processes that form.

3 Types of Rocks

1. Igneous rock forms when magma, or molten rock, cools and hardens.

2. Sedimentary rock forms when sediment deposits that form when rocks, mineral crystals, and organic matter have been broken into fragments are compressed or cemented together.

3. Metamorphic rock forms when existing rock is altered by changes in temperature, pressure, or by chemical processes.

Chapter 6The Rock Cycle

Geologic forces and processes cause rock to change from one type to another.

rock cycle the series of processes in which rock forms, changes from one form to another, is destroyed, and forms again by geological processes

Chapter 6The Formation of Magma

igneous rock rock that forms when magma cools and solidifies

The three factors that affect whether rock melts include

1) temperature, 2) pressure,3) the presence of fluids in the rock.

Chapter 6The Formation of Magma, continued

Partial MeltingDifferent minerals have different melting points

As the temperature increases and as other minerals melt, the magma’s composition changes.

Chapter 6The Formation of Magma, continued

Fractional Crystallization

The crystallization and removal of different minerals from the cooling magma.

Minerals that have the highest freezing points crystallize first.

Chapter 6Textures of Igneous Rocks

intrusive igneous rock rock formed beneath Earth’s surface

extrusive igneous rock rock formed at Earth’s surface

Chapter 6Textures of Igneous Rocks, continued

Coarse-Grained Igneous RockBecause intrusive igneous rocks cool slowly, they

commonly have large mineral crystals.

Fine-Grained Igneous RockBecause extrusive igneous rocks cool rapidly, they

are commonly composed of small mineral grains.

Sedimentary Rock

1. Rocks, mineral crystals, and organic matter that have been broken into fragments .

2. Sediment is carried away and deposited by water, ice, and wind.

3. Sediment deposits are compressed or cemented together and harden they form sedimentary rock.

Section 3 Sedimentary RockChapter 6Chemical Sedimentary Rock

chemical sedimentary rock sedimentary rock that forms when minerals precipitate from a solution or settle from a suspension

Section 3 Sedimentary RockChapter 6Organic Sedimentary Rocks

organic sedimentary rock sedimentary rock that forms from the remains of plants or animals

Section 3 Sedimentary RockChapter 6Organic Sedimentary Rocks,

continuedThe diagram below shows the formation of organic limestone.

Section 3 Sedimentary RockChapter 6Clastic Sedimentary Rock

clastic sedimentary rock sedimentary rock that forms when fragments of preexisting rocks are compacted or cemented together

Chapter 6Formation of Metamorphic Rocks

One type of rock changes into metamorphic rock because of chemical processes or changes in temperature and pressure

Heat, pressure, and hot fluids cause some minerals to change into other minerals.

Chapter 6Formation of Metamorphic Rocks, continued

Contact MetamorphismA change in the texture, structure, or

chemical composition of a rock due to contact with magma

Regional Metamorphism

A change in the texture, structure, or chemical composition of a rock due to changes in temperature and pressure over a large area, generally are a result of tectonic forces

Chapter 6Classification of Metamorphic Rocks

Foliated RocksMinerals grains are arranged in planes or

bands

Extreme pressure may cause the mineral crystals in the rock to realign or regrow to form parallel bands.

Chapter 6Classification of Metamorphic Rocks, continued

Nonfoliated RocksMinerals grains are not arranged in

planes or bands