EARTHS MATERIALS
ROCKS AND MINERALS
MINERALS VS ROCKS
• MINERAL is a naturally occurring inorganic solid
with a crystal structure and a characteristic
chemical composition.
• These are the building blocks of rocks.
• Granite is an example you can see the individual
crystals
Properties of Minerals
• Crystal structure: The arrangement of the
atoms.
• The difference in the crystal structures
between these two
minerals offers an
idea of the
diversity of
crystalline forms.
Color
• Color: Some can be deceptive like quartz.
Streak
• Streak: Scrape the mineral on an unglazed
porcelain plate and observe the color.
http://faculty.chemeketa.edu/afrank1/rocks/minerals/streak.htm
Luster
• Metallic/Nonmetallic Luster The luster of a
mineral is the way its surface reflects light.
Most terms used to describe luster are selfexplanatory: metallic, earthy, waxy, greasy,
vitreous (glassy), adamantine (or brilliant, as
in a faceted diamond). It will be necessary, at
least at first, only to distinguish between
minerals with a metallic luster and those with
one of the non-metallic lusters.
http://faculty.chemeketa.edu/afrank1/rocks/minerals/luster.htm
Density
Mass / volume
Please see chart on page 667
Hardness
• Hardness is the resistance of a mineral to
scratching.
• Diamond is the hardest mineral with a rating
of 10.
Fracture and Cleavage
• Fracture: how a mineral breaks
• Cleavage: a type of fracture
where the mineral
splits along regular
well defined planes.
• Do Data analysis pg 667
• Section assessment pg. 669
Rocks and the Rock cycle
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Three major groups of rocks
Igneous
Sedimentary
Metamorphic
This is based on how they are formed
http://sharksrulescienceiscool.weebly.com/rocks--minerals.html
Igneous rock
• This rock forms from magma
• This forms when molten material cools and
solidifies either inside the earth or on the
surface.
• Intrusive is under the earth, like granite
• Extrusive is on the surface of the earth., like
basalt
Volcanic neck
• A volcanic neck is a cylindrical-shaped
landform standing above the surface created
by magma solidifying in the vent of a
volcano. Erosion of the sides of the volcano
exposes the neck.
• This is a volcanic intrusion that is exposed as
the surrounding soil erodes
Sedimentary
• A rock that forms over time as sediment is
squeezed and cemented together.
• Three types:
• Clastic
• Chemical
• Organic
Clastic Rocks
• Made from the broken fragments of other
rocks.
Chemical Rock
• Minerals precipitate out of a solution
Iron Ore is a chemical
sedimentary rock that forms
when iron and oxygen (and
sometimes other substances)
combine in solution and deposit
as a sediment. Hematite
(shown above) is the most
common sedimentary iron ore
mineral. The specimen shown
above is about two inches (five
centimeters) across.
http://geology.com/rocks/sedimentary-rocks.shtml
Organic Rock
Coal is an organic
sedimentary rock that
forms from the
accumulation and
preservation of plant
materials, usually in a
swamp environment.
http://geology.com/rocks/sedimentary-rocks.shtml
Metamorphic
• Rock change by temperature, pressure or
chemical reaction with hot water.
• The original rock can be any type. The results
is a new type of rock.
• It can also have a new mineral content.
• A new texture
Rock Cycle
Rock lab
• http://www.rockhounds.com/rockshop/rockk
ey/index.html#granite
• To help Identify rocks you brought from home.
The End