Rocks and Minerals

SC.4.E.6.1 Identify the three categories of rocks: igneous, (formed from molten rock); sedimentary (pieces of other rocks and fossilized organisms); and metamorphic (formed from heat and pressure).

SC.4.E.6.2 Identify the physical properties of common earth-forming minerals, including hardness, color, luster, cleavage, and streak color, and recognize the role of minerals in the formation of rocks.

How are ROCKS formed?

ADD

ADD

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Two or more minerals

Once-living animals

Organic plant matter

ROCKS

CLASSIFICATION OF ROCKS

TYPES OF ROCK

DEFINITION

Metamorphic

Rockrock formed from extreme heat and pressure

Igneous

Rockrock formed from the cooling of magma or lava

Sedimentary

Rockrock formed from many layers of sediments that

become pressed and cemented together

M E T A M O R P H I C R O C K S

.

Formed when igneous and sedimentary rocks are exposed to extreme heat and pressure.

Quartzite Marble Slate

E X A M P L E SE X A M P L E S

I G N E O U S R O C K S

.

Formed when molten rock is cooled.

Granite Obsidian Basalt

E X A M P L E SE X A M P L E S

S E D I M E N T A R Y R O C K S

.

Formed when smaller pieces of rock and fossilized organisms are pressed and cemented together.

Limestone Shale Coal

E X A M P L E SE X A M P L E S

T H E R O C K C Y C L E

.

C O M M O N M I N E R A L S

Talc

Pyrite

Graphite

Quartz

Feldspar

Mica

Calcite

COMMON CHACTERISTICS USED TO CLASSIFY MINERALS

HARDNESSTo determine hardness, one mineral is rubbed against another to see if it will

result in being scratched.

HARDNESS FACTS

Quartz and feldspar can scratch both glass andsteel and are considered hard minerals.

Diamond is the hardest natural substance on Earth, while talc is the softest mineral.

Talc is so soft that your fingernail can easily scratch it.

HARDNESS SCALE OF MINERALS AND OTHER OBJECTS

HARDNESS MINERAL

1 Talc2 Graphite3 Calcite and Mica

4 Fluorite

5 Feldspar

6 Pyrite

7 Quartz8 Topaz

9 Corundum

10 Diamond

HARDNESS OTHEROBJECTS

2.5 Fingernail3 Copper Penny

5.5 Glass

7.5 Concrete Nail

COMMON CHACTERISTICS USED TO CLASSIFY MINERALS

COLOR Many minerals exist in different colors and some minerals have identical colors to others.

Pink

ROSE QUARTZ GRAPHITE

Steel Grey

COMMON CHACTERISTICS USED TO CLASSIFY MINERALS

LUSTER A mineral's luster describes the way

light is reflected from its surface.

EXAMPLE

GLASSYDULL

BRILLIANT

WAXYPEARLY

Pyrite is the classic "Fool's Gold“It is commonly mistaken for gold.

METALLIC

METALLICADJECTIVES DESCRIBING LUSTER

COMMON CHACTERISTICS USED TO CLASSIFY MINERALS

CLEAVAGEOccurs when a mineral breaks along a smooth definite line.

CLEAVAGE

IMPERFECT

GOODPERFECT

POOR

GOOD CLEAVAGE

PERFECT CLEAVAGE

MICACALCITE

COMMON CHACTERISTICS USED TO CLASSIFY MINERALS

STREAKThe powder color of a mineral left behind

when the mineral is rubbed against a streak plate or a porcelain tile.

STREAK PLATE

COMMON CHACTERISTICS USED TO CLLASIFY MINERALS

STREAK COLOR CHART

MINERAL STREAK COLORQuartz White

Feldspar WhiteMica White

Calcite WhiteTalc White

Pyrite BlackGraphite Black to Steel Gray