The Rock Cycle. Elements in the Earth’s ATMOSPHERE Element Amount Nitrogen78.1 % Oxygen20.9 % Argon0.96 %

TheRock Cycle

Elements in the

Earth’s ATMOSPHERE

Element Amount

Nitrogen 78.1 %

Oxygen 20.9 %

Argon 0.96 %

Elements in the

Earth’s OCEANS

Element Amount

Oxygen 85.84 %

Hydrogen 10.82 %

Chlorine 1.94 %

Sodium 1.08 %

Magnesium 0.1292 %

Elements in the

Earth’s CRUSTElement

Oxygen

Silicon

Aluminum

Iron

Calcium

Amount47 %

28.2 %

8.23 %

5.63 %

3.5 %

IGNEOUS ROCKS• Forms from cooled lava.

• Most have crystals… the size of the crystal depends on how fast the lava cooled.

- Slow cooling = large crystals - Fast cooling = small to microscopic • Some rocks have pores (like a sponge) from

the gases in the lava escaping during the cooling process.

Uses of Igneous Rocks

• Road building materials• Gravestones• Creating lasting monuments• Used as an abrasive in polish things.• For trim and decoration in buildings. • Decorative landscape stone. • Jewelry

IGNEOUS ROCKSGranite Obsidian

GabbroPumice

Igneous rock forms in two ways!

Intrusive

- Forms from magma cooling and solidifying inside the earth’s crust.

Extrusive

- Forms from lava cooling and solidifying outside of the earth’s crust.

SEDIMENTARY ROCKS

• Formed from weathered igneous and metamorphic rocks that are compacted and cemented together!

• Usually layers can be seen. • Some are conglomerates… i.e. you

can see smaller rocks or shells embedded.

Uses of Sedimentary Rocks

• Gypsum is used to make plaster of Paris and in drywall.

• Sandstone and limestone are used as building stones.

• Limestone is also used for hard core cement roads.

SEDIMENTARY ROCKSConglomerate Shale

Banded-SandstoneLimestone

METAMORPHIC ROCKS

Formed within the Earth… rocks that undergo an extreme amount of heat and pressure.

These rocks are usually very dense rocks.

Uses of Metamorphic Rocks

• Used for pool table tops • Carved into statues • Buildings materials (floor tiles roofing

tiles and counter tops)• Jewelry = Diamonds

METAMORPHIC ROCKSMarble Slate

Mica Schist Quartzite

Rock Cycle

The Importance of Rocks and Minerals

IgneousObsidian Used in making arrowheads and knives Basalt Used in road building materials PumiceUsed in scouring, scrubbing, and polishing

materials Granite Used for buildings, monuments, and

tombstones

The Importance of Rocks and Minerals

SedimentarySandstone Used in the building industry for houses Gypsum (mineral) is used to make plaster of Paris and in

drywall

Limestone is also used for hard core cement roads.

The Importance of Rocks and Minerals

MetamorphicMarble Used in building, floors, tile in

bathrooms Slate Used forroofs, chalkboards, patio walks

and pool tables

The Importance of Rocks and Minerals

MineralsCalcite Used in cements and mortars and

the production of lime QuartzUsed in making glass, electrical

components, and optical lenses

Physical Properties of Rocks and Minerals

MineralsA mineral is…

• Naturally occurring

• Inorganic- (made up of none living things)

• Definite chemical composition & crystal structure

• Solid

All physical properties of minerals come from the “internal arrangement of atoms”

Mineral Identification Tests

• The Streak Test

• The Color Test

• The Luster Test

• Hardness (Moh’s Scale)

• Cleavage

• Crystal Shape

• Reactions with Acids

• Specific gravity

The Streak Test• The color of the powdered mineral

performed by rubbing the unknown mineral on an unglazed tile.

The Luster Test• The way a mineral shines or doesn't shine

• The only way to really learn the different luster's is to see them for yourself.

• 2 Types of Luster

• Metallic and Non-Metallic

• Metallic Luster

Rocks look

like shiny metal

• Ex. Hematite

Non-Metallic Luster• Non-metallic- all the other ways that a mineral can

shine – Glassy- shines like a piece of broken glass (most

common non-metallic) – Dull/earthy- no shine at all – Resinous/waxy- looks like a piece of plastic or dried

glue – Pearly- looks oily it may have a slight rainbow like an

oil slick on water. Also looks like the inside of some clam shells

– Adamantine- brilliant, sparkling shine like a diamond

Color Test• Color is used to determine the type

of rock but it is not always reliable. • Sulfur is (almost) always yellow,

and there are a few others, but not many minerals have a fixed color. Small amounts of impurities can drastically change a mineral's color.

Hardness Test• Hardness- a minerals resistance

to scratching. • This should not be confused with

brittleness. A diamond is very hard and will scratch a hammer but a hammer will smash a diamond.

Moh’s Scale of Hardness• Talc (Softest)

• Gypsum • Calcite • Fluorite • Apatite

• Feldspar (AKA Albite) • Quartz • Topaz

• Corundum • Diamond (Hardest)

Cleavage Test• Cleavage –The rocks

will break along flat surfaces or…

• Cubic- Rocks will break into cubes.

Crystal Formation• Minerals will grow

crystal formations when given time & space to grow.

• Can be recognized by their beautiful regular shapes once you have seen a few examples.

Quartz Crystal Formation

Miscellaneous Tests• Acid- Calcite and powdered dolomite will

Effervescence (fizz) in diluted hydrochloric acid (HCl)

• Smell- Sphalerite will give off a rotten-egg smell when streaked on a streak plate. Magnetism- Magnetite (AKA Lodestone) will pick up paper clips

Miscellaneous Tests Cont.

• Taste- Halite is rock salt and will taste salty.

• Fluorescence- some minerals (mostly forms of calcite) will glow in fluorescent colors under a black (UV) light.

• Double refraction- some clear forms of calcite (Iceland Spar) will make a double image of words.

Specific gravity• Specific gravity indicates how many times more

the mineral weighs compared to an equal amount of water .

• Since water has a density of 1 gram/cm3, and since all of the units cancel, specific gravity is the same number as density but without any units.

• Remember… Density = Mass / Volume

• Density is how much matter packed in a space.