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Rock On! Igneous Rock
Metamorphic Rock
Sedimentary Rock
All rocks are
made of
MINERALS!!!!
graphite quartz salt
• Minerals inorganic solid materials
found in nature. 4,000 different kinds
of minerals exist!
• Inorganic means not formed by
plants or animals.
• All minerals look and feel
different from one
another. You can use
physical properties to tell
different mineral apart.
gold silver
calcite
sulfur
How minerals form… • From melted rock inside the earth called magma
(reaches earth surface called lava) cools and
combines to form minerals.
lava
magma
Scientists classify rocks
by using two important
criteria
granite lead
marble salt rock The minerals that the rock is made of!!!!
•Determined by the shape, size, arrangement, and distribution of rock’s
mineral grains •Provides clues for how and where rock
formed
Glassy Texture Rocks have NO visible grains!
Obsidian
Rocks have small visible grains!
Fine-Grained Texture
Basalt
Shale
Rocks have large visible grains!
Course-Grained Texture
Granite
Gneiss
Rocks have small and large
visible grains!
Porphyritic Texture
Granite
Rhyolite
Rhyolite
Textures Glassy Course
Grained
Fine
Grained Porphyritic
Three Types of Rocks
Igneous Rocks
Sedimentary Rocks
Metamorphic Rocks
•Igneous means
•Igneous rocks form
when
and hardens
DIORITE OBSIDIAN
GRANITE
BASALT
Two Types of
Igneous Rock
Extrusive
Rock
Intrusive
Rock
Intrusive (inside) rock
that forms when magma
cools below earths surface.
• Takes a LONG time to
cool, so large grains form
• Usually course-grained
PEGMATITE
DIORITE
Extrusive (exit) rock that forms
when lava cools on the earths
surface.
• Cools very quickly, so only small
crystal may appear
• Usually have fine- grained texture
BASALT
OBSIDIAN
RHYOLITE
• Extrusive rock forms in 2 ways
–Volcano shoots it out
–Fissures (cracks in the earth’s crust where lava oozes out)
fissure
•Form as sediments
become compacted and
cemented together
• Sediments are pieces of rock, shells, minerals and grains.
3 types of sedimentary rock
• Clastic rock
• Chemical rock
• Organic rock
• Clastic rock forms when wind or water moves
fragments of other rocks and minerals close together.
• Minerals in dissolved water cement these particles
together. Weight of new sediments on top of the old
compress them even tighter.
Weight of
new sediment
Pressing on old
sediment
Clastic Sedimentary Rock
Conglomerate
Sandstone
Chemical rock
• rock formed when water high in mineral
content such as in oceans or geysers
evaporates leaving the sediments behind.
• NOT made from pre-existing rock
Chemical Sedimentary Rock
• Limestone
• Organic rocks rock that comes from
dead organisms that have been dead over
millions of years.
• Examples: coal, fuel
1 year
later
Bones break down
Turns into dust
10 years
later
More animals
Die dead animal
Particles slowly
Get stacked on top
Of each other
100 years later
1000 years
New animal
particles
Old animal
particles
Old
new
pressure
Organic rock is
made from
fossils (remains
or traces of once
living plants or
animals)
Organic Sedimentary Rock
• Coquina
Fossiliferous Limestone
•Metamorphic comes from “META” which
means changed and “MORPHOS” which
means shape
•Form when sedimentary, igneous or other
metamorphic rocks are exposed to intense
heat and pressure
• New rock can be changed to different kinds of rock by adding heat and pressure. The new type of rock formed is called metamorphic rock.
Heat and pressure
limestone marble
• 2 types of metamorphic rock
• Foliated rocks with visible layers
• Nonfoliated rocks with no visible layers
nonfoliated foliated
• Rock cycle constant changing of rock
from one type to another.