TOPIC 10 Minerals, Rocks and Mineral Resources
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Transcript TOPIC 10 Minerals, Rocks and Mineral Resources
TOPIC 11
Minerals, Rocks and Mineral
Resources
**Rocks and minerals make up the Earth’s Surface.**
Minerals = a naturally occurring, inorganic, crystalline
solid having a definite chemical composition.
~ it is inorganic because it has not been made or
composed of life forms.
~ it is crystalline because its atoms have a specific
arrangement, this is called a crystalline structure.
Rock = a naturally formed solid that is a part of Earth or
any other celestial body.
Element Composition of the Earth’s Crust
99 percent of the Earth’s crust is composed
of only 8 to 90 naturally occurring elements.
The Earth’s most abundant (amount
existing) element in the crust is oxygen (O)
followed by silicon (Si). Refer to Reference
Tables pg. 11.
In the ESRT, they list the abundant
elements by volume and by mass. Make
sure you choose the right value when
asked.
Mono-mineralic – made up of only 1 mineral.
Ex: salt
Poly-mineralic – made up of 2 or more
minerals.
Ex: Granite
**There are over 2,000 minerals but only a few rock forming
minerals.**
Feldspar
Augite
Quartz
Garnet
Mica
Magnetite
Calcite
Olivine
Hornblende
Pyrite
Kaolin
Talc
Mineral Crystal Structure
The mineral structure (internal arrangement of
atoms) is responsible for many of its chemical
and physical properties.
Ex: Graphite / Diamond have the same
chemical composition but different
properties, ie: hardness and shape.
Most rock forming minerals are silicates
(meaning they contain silicon (Si) and oxygen
(O).
Minerals form by recrystallization of atoms –
the arrangement of the matter as it turns to a
solid.
Mineral Identification
There are 6 ways to identify a mineral:
1) Color – some minerals have distinctive colors.
Some minerals tarnish – not true color
2) Streak – color of a mineral in its powdered form.
Most minerals have a clear or white streak.
3) Luster – how a mineral reflects light.
a) metallic – shines like polished metal
b) non-metallic – does not shine like polished
metal. A non-metallic luster can be glassy,
pearly, dull, waxy or earthy.
4) Hardness – a mineral’s resistance to being scratched
a) A harder mineral will scratch a softer mineral
b) Mohs Scale of Hardness – a scale that ranges from 110, 1 being the softest and 10 being the hardest.
Fingernail – 2.5
Penny – 3.0
Glass – 5.5
Steel file – 6.5
5) Cleavage – a mineral’s ability to split along flat surfaces. This
is due to the internal arrangement of atoms.
Example: Halite (salt) – NaCl
* This mineral breaks off into small cubes
* Fracture – when a mineral breaks leaving an
irregular/uneven surfaces
6) Specific gravity – density of a mineral compared to the
density of water. The specific gravity of water is 1.
Example: Mineral x has a specific gravity of 3. (This
means it is 3x’s the density of water)