Minerals
Humans cannot survive without
minerals
• 16 minerals needed
for humans to survive
• .03% of what we eat
but we would not
survive without the
minerals
• Sodium, potassium,
calcium, magnesium,
copper, phosphorous
Minerals make-up many
practical parts of our lives
Glass is made from 6 minerals
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Silica
Limestone
Magnesium
Boric acid
Soda
Aluminum
40 billion glass
containers/year in USA
• 35 % are recycled
Gold in California
• Discovered in the
American River, 1848
• Gold Rush- 1849
• Population of SF- 575
males,177 females, 60
children- March, 1848
• 100,000- December 1849
• Chinese, Welsh, German,
English, Mexican,
Spanish and French
• Diversity of California
Salt
• Early people collected salt
before they understood
how important the mineral
is for survival
• Mediterranean-salt cakes
were used as money
• Greeks traded salt for
slaves
• England flourished when
fuel for boiling brine
changed from wood to coal
Minerals are mined for our use
Magmatic copper, magnetite, uranium
What is a mineral?
• Naturally occurring
• Inorganic
• Crystalline structure
Halite, salt, sodium
chloride
Atoms make-up minerals
• An atom is the
smallest component
of matter
• Each element is
defined by the
number of protons
• The atom must be
electrically neutral
• The number of
protons equals the
number of electrons
http://www.howstuffworks.com/atom/htm#
Eight elements make-up 99% of
the Earth’s crust
Silicon and oxygen make-up 70 % of the Earth’s crust
Why do atoms combine to form
minerals?
• Write the following questions and
answer in your notes:
• Look at the salt with the hand lens
• What is the color?
• What is the shape of the crystals?
• Does the shape match the halite crystals?
• What is a distinguishing characteristic of
salt?
Salt is also named Sodium
Chloride
• Look at the periodic table:
• Write the chemical notation, atomic
number and atomic weight for sodium and
chlorine
• Now sketch an atom with the nucleus
containing the correct number of protons
and neutrons
• Sketch the electrons on the “rings” around
the nucleus
Sodium chloride: sketch a
diagram of the sodium and
chlorine atoms
Why do sodium and chlorine
combine to form salt?
• Explain why sodium and chlorine combine
to form salt
The configuration of electrons
determines if an atom will respond
with another atom
The sodium atom has one electron on its outer ring. The Chlorine atom
has 7 electrons on its outer ring. The two atoms share electrons
forming an ionic bond.
Atomic structure determines the
mineral’s characteristics
Salt or halite always has a cubic form and tastes salty.
Cations and Anions
• The one electron on
the outer shell is
given up
• This leaves the
sodium atom with
more protons, +1
cation
• The one electron is
added to Chlorines
outer shell
• This leaves the
chlorine atom with
one more electron, -1
anion
Mineral
Formation
• Cooling of magma:
crystallization
• Evaporation: salt
• Hydrothermal
Silicate minerals are the building
block of igneous rocks
Granite: individual minerals
make-up the rock
Mountains, British Columbia
Minerals are the building block
of rocks
Quartz
Biotitie
Feldspar crystal
Hornblende
Minerals can be identified by
physical properties
• Crystal habit
• Cleavage
• Fracture
Quartz has a conchoidal fracture
Equant garnet: same dimension in
all directions
Mica has a single, perfect cleavage
Color
malachite
apatite
sulfur
Hardness
How the mineral can
be scratched
• Fingernail
• Penny
• File or knife
Streak
• Minerals leave a
distinct residue on a
porcelain plate
Luster
• Metallic or non-metallic
Classification of Minerals
• Composition
• Rock forming
minerals contain
silicon and
oxygen
The silicon
tetrahedron
The arrangement of the silicon
tetrahedron determines the
mineral’s shape
Hornblende:
double chain
Olivine
Biotite: sheet structure;
breaks easily on one
surface
Mineral Classification: based on
dominant element
Sulfides: contains the element sulfur
Pyrite: fool’s gold; FeS2
Galena: PbS; important ore of
lead
Mineral Classification: based on
dominant element
• Carbonates: contains calcium carbonate; CaCO3
Calcite: CaCo3
Dolomite: CaMg(CO3)2
Summary
• Mineral definition
• How do minerals form?
• Read and understand information associated
with the periodic table of the elements
• Be able to sketch a diagram of an atom:
hydrogen, helium, carbon, sodium, chlorine
• How are minerals classified: rock forming
minerals? Silicates, sulfides, carbonates
• Name and describe the physical characteristics
to distinguish minerals.