51
3. The geosphere
www
2.2.
The importance of minerals
Throughout history, the ability to identify minerals and to obtain raw materials has
been essential to the success of civilizations.
Today, minerals are used mainly as metal
ores
, as raw materials for industry, or sold
as gems or precious stones.
2.2.1.
Metal ores
These are minerals that metals are extracted from (see table on the right). Other
minerals, known as
native
or
noble minerals
are found in nature in their pure
state. Examples of these minerals are gold, silver or platinum, admired since ancient
times for their colour, beauty, easiness to mould and durability.
2.2.2.
Raw materials for industry
These are themost abundant minerals found in the Earth’s crust. Some examples are:
uraninite
which provides us with uranium used as fuel in nuclear power stations;
quartz
, which is very important for manufacturing glass, computer components,
parts and solar panels; and
gypsum
, which is used for manufacturing plaster,
alabaster, fertilisers and explosives.
2.2.3.
Gems or precious stones
These are beautiful and rare minerals which have a great economic value. They are
used for jewellery, usually after a process of cutting and polishing to bring out their
lustre. Some of the most well-known gems are
diamonds
,
rubies
,
sapphires
and
emeralds
.
2.3.
Sustainable management of mineral resources
Uncontrolled mining has an impact on the environment such as contamination of
water and land contamination with metals. It can also cause health problems for
miners: headaches, blood poisoning with lead and mercury, and breathing problems.
Responsible use of minerals is essential to avoid or reduce this negative impact. We
can help by recycling minerals and electronic devices made with minerals such as
mobile phones and computers.
Diamond
Ruby
Sapphire
Emerald
Main ores of some metals
Ore
Metal
Bauxite
Aluminium
Blende
Zinc
Chalcopyrite Tin
Cinnabar
Mercury
Galena
Lead
Hematite
Iron
Key concepts
❚
Minerals are solid, inorganic
substances of natural origin.
They have a definite chemical
composition and most have a
crystalline structure.
❚
They have properties that
allow us to identify them
such as hardness, lustre,
streak or density.
❚
They are used as metal ores,
as raw materials for industry
and as gems or precious
stones.
❚
The responsible use of
minerals reduces the impact
of their extraction on the
environment.
Analyse
15.
Find out about the use of the metals extracted from these mineral
ores: bauxite and cinnabar. Write a short report in your notebook.
16.
Find out about the hardness of the gems in the photos above. Do you
think their economic value is related to their hardness? Explain your
answer.
