Are you ready to rock?
- Rocks and minerals surrounds us. From diamonds, to
granite counters, they are widely used in our lives.
- In this section you will be learning about rocks and
minerals.
- You will notice however, that they are made up of many
elements that you might be familiar with.
- Let’s check it out:
www.rocksandminerals4u.com/minerals.html
A trip to Italy…
Carrara, near Florence is a mountain of natural marble! What a
beauty!
A trip to Greece… (the island of Santorini)
Santorini is an extinct volcano.
A trip to Prince Edward Island
The Island is formed from sedimentary bed rock of
soft, red sandstone which produces the rich, red soil.
The redness of the soil is due to the high iron-oxide
(rust) content.
QUICK REVIEW OF THE EARTH’S LAYERS AND
LITOSPHERE P290 AND 302
- Our planet is divided into three main layers: the crust, the mantle and the core.
The lithosphere p302
• The lithosphere is a SOLID structure that
includes the Earth’s crust and part of the
upper mantle.
• It is important for:
– Plants to grow, that is where they get their
minerals.
– Several animal’s habitat
– Natural resources such as crude oil
The lithosphere
The rock cycle
Voir le site web:
http://www.classz
one.com/books/ea
rth_science/terc/c
ontent/investigatio
ns/es0602/es0602
page02.cfm
Igneous rocks
• Igneous rocks are formed when magma cools down
EXTRUSIVES
INTRUSIVES:
Slow cooling of magma under the crust.
Ex: gabbro, granite
Fast cooling of magma outside of the
crust.
Ex: obsidian
Pumice rock
Sedimentary rock
• When igneous rocks move by erosion: (wind, rain, other
climatic conditions)
• Debris pile up under water to give sedimentary rock.
Fossils are found in
sedimentary rocks.
Ex: calcite (like chalk)
Below is shale, a rock formed by compression of layers of
sediments
calcite
Shale
Metamorphic rocks
• When sedimentary or igneous rocks are compacted
under the crust, they turn into metamorphic rock.
• They are the effect of high pression and high heat.
Gneiss is
metamorphosed granite
Marble is
metamorphosed calcite
Hardness scale
• If you compare a piece of glass with a wooden
hammer, which you think will be hardest?
Which brakes easily?
Glass, of course will break easily.
BUT glass is harder than wood
because it can scratch it!
And wood cannot scratch glass.
• Diamonds can scratch glass BUT glass can’t
scratch diamonds!
-Hardness Is a characteristic property of
matter. It is the ability to resist a scratch or
change of shape.
- We use the hardness of minerals, like
gemstones and rocks based on the Mohs
Scale.
-This scale was developed in the 19th century by
Frédéric Mohs (1173-1839) a german
minearologist.
• Mohs numbered ten minerals 1 to 10.
• Each can scratch a mark on minerals with
lower numbers
-Example1: Topaz (hardness 8) can scratch quartz (hardness 7), but not diamond (hardness
10)
The fingernail can scratch gypsum (h 2) but not calcite, so its hardness is 2.5.
Hardness of various objects
-Fingernail: 2,5
-Penny : 3
-Glass slide: 5,5
-Steel Nail: 6,5
-Porcelain plate: approx 7
Find the approximate hardness of the minerals in your
lab show your work
Mica
Pyrite
Galena
Quartz
MICA
QUARTZ
PYRITE
GALENA