Rocks and Minerals€¦ · Metamorphic Rocks Because their mineral grains grew together tightly...
Transcript of Rocks and Minerals€¦ · Metamorphic Rocks Because their mineral grains grew together tightly...
Rocks and Minerals
What is this rock made up of?
Mica
Feldspar
Quartz
What is a mineral?
Mineral: solid, inorganic, pure substance which:
Occurs naturally
Has an ordered atomic structure which forms crystals.
There are 4000 known minerals on Earth.
What is a mineral?
Minerals rarely occur in a pure form.
They need to be mined.
When minerals are extracted from the
lithosphere, they are called ore.
Ore: rock containing a mineral that is mined
for profit
Please turn to page 303
A rock: A composition of minerals
Rocks are highly compacted minerals formed
through volcanic processes
They are not pure substances as they contain
many materials
Let’s explore some minerals
Commonly used minerals
Gold- used in jewellery
Sodium chloride - used as table salt
Beryllium- Found in emeralds
Pyrite- Used in alcohol preservation, also
known as fool’s gold
Magma: The one responsible
As molecules are being pushed upwards,
they will “clump” together.
The resulting clumping towards the Earth’s
surface solidifies the minerals.
Minerals closer to the surface contain
SMALLER more FINE molecules.
Crystals: The inner shape of
minerals
Highly crystallized structures
The resulting solid from solidification of
magma is seen under the microscope as fine
crystals.
Many minerals share the same crystalline
structure
Between a rock and a hard place
Rocks that cooled more SLOWLY contain
minerals solids that are larger
Which is why we can see the minerals clearly
Granite is an example
Between a rock and a hard place
Rocks that cooled more QUICKLY contain
minerals solids that are smaller
Which is why we cannot see the minerals
clearly
Basalt is an example
Igneous rock
Igneous rock is formed by magma (molten
rock) being cooled and becoming solid
Approximately 90% of Earth’s crust
Black, white or gray
Lots of holes
Black bread
Sedimentary rocks
Results from sediments and small particles
being carried away by erosion of the Earth
These sediments then accumulate over
million of years to give us LAYERS.
5% of Earth’s surface
Sedimentary rocks
They're usually the color of sediment, that is,
light brown to light gray.
They may preserve signs of life and surface
activity, like fossils, tracks, ripple marks and
so on.
Metamorphic rock
A rock that has been trapped under the
Earth’s crust for a long time. Often thousands
of years.
It is being chemically transformed by the heat
and pressure of the Earth’s crust
Examples are schist, slate and marble
Metamorphic Rocks
Because their mineral grains grew together tightly
during metamorphism, they're generally strong
rocks.
They're made of different minerals than other kinds
of rocks and have a wide range of color and luster.
They generally show signs of stretching or
squeezing, giving them a striped appearance.