Earth and Life Science Lesson 5

1. MINERALSMINERALS

2. Learning objectivesLearning objectives
 describe how much minerals are part ofdescribe how much minerals are part of
our daily livesour daily lives
 describe minerals as a life-long hobbydescribe minerals as a life-long hobby
(gemstone collectors)(gemstone collectors)
 describe the importance and use ofdescribe the importance and use of
minerals to human developmentminerals to human development
 develop a systematic way of identifyingdevelop a systematic way of identifying
mineralsminerals

3. What is a Mineral?What is a Mineral?
 Naturally OccurringNaturally Occurring
 InorganicInorganic
 SolidSolid
 Definite Chemical FormulaDefinite Chemical Formula
 Definite Crystal StructureDefinite Crystal Structure

4. Naturally OccurringNaturally Occurring
 Formed by natural processes not in theFormed by natural processes not in the
laboratorylaboratory
- Is an Ice Cube a mineral?- Is an Ice Cube a mineral?
- Is the ice on the windshield of a car a- Is the ice on the windshield of a car a
mineral?mineral?

5. InorganicInorganic
 Formed by inorganic processes; not livingFormed by inorganic processes; not living
 Does not contain chains of carbon atomsDoes not contain chains of carbon atoms

6. SolidSolid
 Not gas or liquidNot gas or liquid
-H-H22O as ice in a glacier is a mineral, butO as ice in a glacier is a mineral, but
water is notwater is not

7. Definite Crystal StructureDefinite Crystal Structure
 Highly ordered atomic arrangement ofHighly ordered atomic arrangement of
atoms in regular geometric patternsatoms in regular geometric patterns
8
Apatite Feldspar Diamond Quartz

8. Definite Chemical FormulaDefinite Chemical Formula
 Minerals are expressed by a specificMinerals are expressed by a specific
chemical formulachemical formula
-Gold (Au)-Gold (Au)
-Calcite (CaCO-Calcite (CaCO33))
-Quartz (SiO-Quartz (SiO22))
-Pyrite (FeS-Pyrite (FeS22))

10. Mineral PropertiesMineral Properties
Mineral Name Halite (Table Salt)
Chemical
Composition
NaCl
Luster non-metallic – vitreous; transparent to
translucent
Hardness soft (2-2.5)
Color white
Streak white
Crystal Form / Habit cubic
Cleavage perfect cubic
Specific Gravity Light (2.2)
Other Properties salty taste; very soluble, produces reddish spark
in flame

11. LusterLuster
 General appearance of a mineral surface inGeneral appearance of a mineral surface in
reflected lightreflected light
Glassy-Obsidian

12. HardnessHardness
 Resistance to scratching by differentResistance to scratching by different
items; “scratchability”items; “scratchability”
Mohs Hardness ScaleMohs Hardness Scale
>2 fingernail>2 fingernail
3 penny3 penny
~5 Steel of a pocket knife~5 Steel of a pocket knife
5.5 Window Glass5.5 Window Glass
6.6 Steel of a file6.6 Steel of a file
7 quartz crystal7 quartz crystal

13. Mohs Mineral HardnessMohs Mineral Hardness
ScaleScale
1) Talc1) Talc
2) Gypsum2) Gypsum
3) Calcite3) Calcite
4) Flourite4) Flourite
5) Apatite5) Apatite
6) Feldspar6) Feldspar
7) Quartz7) Quartz
8) Topaz8) Topaz
9) Corundum9) Corundum
10) Diamond10) Diamond
Softest
Hardest
1
2
3
4
5
6
7
8
9
10

14. ColorColor
 Usually the first and most easily observedUsually the first and most easily observed
QUARTZROSE QUARTZ SMOKY QUARTZ

15. StreakStreak
 The color of a finely powdered mineralThe color of a finely powdered mineral
 Determined by rubbing the mineral on a pieceDetermined by rubbing the mineral on a piece
of unglazed porcelain (streak plate)of unglazed porcelain (streak plate)

16. Crystal Form/HabitCrystal Form/Habit
 It is the natural shape of the mineral before theIt is the natural shape of the mineral before the
development of any cleavage or fracture.development of any cleavage or fracture.
 prismatic, tabular, bladed, platy, reniform and equant.prismatic, tabular, bladed, platy, reniform and equant.
 A mineral that do not have a crystal structure isA mineral that do not have a crystal structure is
described asdescribed as amorphousamorphous

17. CleavageCleavage
 is the tendency of a mineral to split oris the tendency of a mineral to split or
crack along parallel or flat planescrack along parallel or flat planes
BIOTITE
QUARTZ
No Cleavage1 Direction of Cleavage

18. FractureFracture
 occurs when a mineral breaks at randomoccurs when a mineral breaks at random
lines instead of at consistent cleavagelines instead of at consistent cleavage
planes.planes.
Obsidian
Conchoidal Fracture

19. Specific GravitySpecific Gravity
 –– It is the ratio of the weight of a mineral toIt is the ratio of the weight of a mineral to
the weight of an equal volume of water.the weight of an equal volume of water.
 It is a measure to express the density of aIt is a measure to express the density of a
mineral.mineral.

20. Special PropertiesSpecial Properties
 Magnetism (Magnetite)Magnetism (Magnetite)
 Glowing under ultraviolet lightGlowing under ultraviolet light
(Fluorite)(Fluorite)
 Salty taste (Halite)Salty taste (Halite)
 Smell (Sulfur)Smell (Sulfur)
 Reaction to HCl (Calcite)Reaction to HCl (Calcite)
Magnetite

21. Mineral GroupsMineral Groups
 1. Silicates – minerals containing 2
of the most abundant elements in
the Earth’s crust, namely, silicon and
oxygen.
 2. Oxides – minerals containing
Oxygen anion (O2-) combined with
one or more metal ions

22. Mineral GroupsMineral Groups
 3. Sulfates – minerals containing Sulfur
and Oxygen anion (SO4)- combined with
other ions
 4. Sulfides – minerals containing sulfur
anion (S2)- combined with one or more
ions.
 5. Carbonates – minerals containing the
carbonate anion (CO3)2- combined with
other elements

23. Mineral GroupsMineral Groups
 6. Native Elements – minerals that form as
individual elements.
 a. Metals and Inter-metals – minerals with
high thermal and electrical conductivity,
typically with metallic luster, low hardness
 b. Semi-metals – minerals that are more
fragile than metals and have lower
conductivity
 c. Nonmetals – nonconductive

24. Mineral GroupsMineral Groups
 7. Halides – minerals containing halogen
elements combined with one or more
elements

25. Economic Importance of MineralsEconomic Importance of Minerals
 Minerals are in many things we see andMinerals are in many things we see and
use everyday such as; bricks, glass,use everyday such as; bricks, glass,
cement, plaster, iron, goldcement, plaster, iron, gold

26. RESOURCESRESOURCES
 https://www.slideshare.net/guestaede6c/minerhttps://www.slideshare.net/guestaede6c/miner
 https://https://
www.slideshare.net/goatkell/rocks-minerals-15www.slideshare.net/goatkell/rocks-minerals-15
 memberfiles.freewebs.com/50/69/6818695
0/documents/chapter%203.ppt
 Earth Science TG
