Download 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)