I.                    Chapter 8  Minerals

A.     Minerals are natural, nonliving solid crystals that make up rocks.

B.     Each mineral has crystals that are a particular shape.

C.     All over the world, each mineral has the same chemical makeup.

D.     All rocks are made of one or more minerals.

E.      Scientists test the physical properties of minerals to identify them.

1.                  color

2.                  luster

a)                  the way it reflects light

b)                  dull,

c)                  metallic

d)                  glassy

3.                  hardness

a)                  how easily mineral can be scratched

b)                  Mohs Scale of Hardness

(1)               minerals ranked 1-10

(2)               higher numbered minerals can scratch lower numbers

(3)               diamond is number 10

(4)               quartz is number 7

(5)               talc is number 1

4.                  streak

a)                  the color of the powder a mineral leaves

b)                  even though a mineral may come in several colors they will have the same color streak

5.                  cleavage

II.                 Sedimentary Rock

A.     Weathering is a natural process that breaks rocks into smaller pieces.

B.     Erosion is caused by wind, ice, gravity, and water that work to move weathered material.

C.     Sediment is the eroded material that settles to the bottom of bodies of water.

D.     Sedimentary rock is formed when many layers of sediment that settle under the water are pressed together and harden from the weight of the top layers.

E.      Three types of sedimentary rock

1.                  formed from hard skeletons and shells of sea animals

a)                  limestone

2.                  formed by bits of quartz the size of a sand grain

a)                  sandstone

3.                  forms in lakes and oceans from very tiny particles

a)                  mudstone

b)                  shale

F.      Fossils

1.                  Fossils are remains or evidence of ancient plant or animal life on Earth.

2.                  Scientists can tell many things from fossils.

a)                  what ancient plant or animal life was like

b)                  what the animal looked like

c)                  what the environment was like

d)                  how the environment has changed since then

III.               Soil

A.     Soil forms when weathering causes rocks to break apart, such as with water, ice, and plant roots.

B.     Soil is made of small bits of weathered rock, decaying plant and animal remains, and tiny life forms.

IV.              Igneous Rock

A.     Forms from molten (melted) rock.

B.     Two types of igneous rock

1.                  Cools quickly

a)                  Magma erupts from a volcano.

b)                  This molten or melted rock is called lava when it reaches the surface.

c)                  It cools quickly not allowing crystals to form.

d)                  Takes a few days to become rock.

e)                  Examples

(1)               Obsidian

(a)                looks like glass

(2)               Pumice

(a)                full of gas

(b)               floats on water

(3)               Basalt

(a)                Most of the ocean floor is basalt.

2.                  Cools slowly

a)                  Magma slowly rises to the Earth’s surface.

b)                  As it rises crystals of minerals form.

c)                  It can take a million years.

d)                  Examples

(1)               Granite

(2)               Pegmatite

(3)               Gabbro

V.                 Metamorphic Rock

A.     These rocks have changed form due to heat and pressure.

B.     Metamorphic rock can be formed from sedimentary, igneous, or other metamorphic rock.

C.     The igneous rock granite can become the metamorphic rock gneiss.

D.     Slate forms from the sedimentary rock shale.

VI.              The Rock Cycle

A.     The recycling of old rock into new is ongoing.

B.     Heat, pressure, chemical reactions, weathering, and erosion are the forces.

C.     Sedimentary rock may melt and become igneous rock without becoming metamorphic rock.

D.     Not all rocks complete the cycle.