Monday November 02, 2009
 Open your notebooks. Write down today’s questions.
 Today’s Theme: What is a mineral?
– What are the ways that minerals can be identified?
– What defines whether something is a mineral or not?
– What is a crystal?
– What is the difference between a rock and a mineral?
 Hand in any late work
 Progress Reports Tomorrow (Due Thursday)
 Science Fair Complete Write Up Due Friday!!!!!!!!! OMG
Minerals
 Today: Use your keen powers of observation to
make a list in your notebook of all of the physical
properties you notice about the six samples.
 Think about these questions:
– Are they all minerals?
– Why do they look the way they do?
– How did they form?
– What are they composed of?
– Where did they come from?
Thursday November 05, 2009
 Please write today’s lesson and date written in your
notebook.
– Today’s lesson: Properties of Minerals
• What are the physical properties of minerals?
• How do we tell minerals apart?
 New Red Books Open to Page 70
 Please do not touch equipment yet!!!!
 Progress Reports Due TODAY (signed by parent)
 Science Fair Complete Write Up is due Tomorrow.
Properties of Minerals
 Learning Objectives
– What are the ways that minerals can be identified?
– What is Moh’s Hardness Scale?
– What is the difference between cleavage and fracture?
– What are some common uses for minerals?
What is a mineral?
 A mineral is
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–
–
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Naturally Occurring (made by earth-not man made),
Inorganic (never was alive),
Solid (atoms in fixed position, definite volume/shape),
with a definite crystal structure (repeating pattern of
minerals atoms),
– and a definite chemical composition (same elements
throughout in a certain proportion)
Which of these are minerals?
AMBER
COAL
MICA
PEARL
SUGAR
QUARTZ
HALITE
Salesite
Gold
Fluorite
Tiptopite (clear) &
Montgomeryite
Acanthite
Asbestos
Gypsum
Pyrite
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Feldspar
Physical Properties of
Minerals
 These properties are used to identify
minerals
1. Color
 Color is the most noticeable physical property of a mineral
but is THE LEAST reliable.
 This is because the same mineral can come in many colors.
Example:
Mineral Identification
Color is one physical property that can be
used to identify minerals but beware……
rhodochrosite
malachite
azurite
turquoise
The many colors of Calcite
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The many colors of Quartz
Streak:
The color of the powdered form of a mineral when
rubbed on an unglazed porcelain plate
Streak
 The mineral is rubbed on an unglazed
porcelain plate to determine the color of the
streak powder.
 Not all minerals have a streak. Any mineral
harder than the plate (7+) will leave a scratch
instead.
Streak Example: Same Mineral!
3. Luster
 Luster describes how light is reflected from a
mineral’s surface.
 A mineral has either
– Metallic Luster (shines like a metal) or
– Non-Metallic Luster.
• Dull, earthy, waxy, greasy, pearly, silky or vitreous (glassy)
Luster:
The mineral
Galena has a
metallic luster
Examples of Luster
Metallic Luster
Non-Metallic
Luster
Metallic or Nonmetallic?
Metallic or Nonmetallic?
Metallic or Nonmetallic?
Density
 Density is the comparison of mass to
volume.
– It’s really how well packed are the atoms in the
object.
Mass divided by volume
5. Hardness
 Hardness is a measure of how easily a mineral
is scratched.
– determined by arrangement of the mineral’s atoms.
Mohs Hardness Scale:
a relative scale used to determine the mineral’s
hardness
5.5
2.5
Fingernail
3.5
Penny
4.5
Iron Nail
6.5
Glass
Streak Plate
Crystal Systems
 The way the mineral grows atom by atom
makes a shape we call a crystal.
– Most of the time you can’t see them.
– More time and space it had to grow = bigger
crystals
Crystal Forms
 These are Quartz
Crystals
These are
Quartz Crystals
Texture
 Texture describes how a mineral feels to the touch.
 Texture can be described as greasy, soapy, glassy,
rough, ragged or smooth.
 Graphite has a greasy texture.
Cleavage or Fracture
 Cleavage - When Minerals break along planes
(layers) where bonding between atoms is weak.
A mineral that splits or breaks easily along
smooth, flat surfaces is said to have cleavage.
•Mica has perfect cleavage in one direction (plane).
•Halite has cubic cleavage (3 planes).
Three Examples of Perfect Cleavage –
Fluorite, Halite & Calcite
Cleavage of Minerals
Cleavage
Cleavage or Fracture
 Minerals that break along rough, jagged or uneven
edges and surfaces are said to have fracture.
– conchoidal (shell-like), splintery, uneven, jagged or
earthy
Conchoidal Example :
Quartz
Don’t be confused between Crystal Faces
(sides) and Cleavage Planes!
- Both minerals in these pictures show Fracture
(not cleavage)
These are
Quartz Crystals
These are
Quartz Crystals
Special Properties
Specific gravity
Reaction to acid
Striations (lines)
Magnetism
Fluorescence
Uses of Minerals
 Gems or Gemstones are highly prized minerals
because they are rare and beautiful.
 An Ore is a mineral that contains a useful
substance that can be mined at a profit.
Ore Name
Gives Us
Hematite
Iron
Chalcopyrite
Copper
Bauxite
Aluminum
Sphalerite
Zinc
Uses of Minerals
Gems: Valuable
minerals prized
for rarity and
beauty.
Ores: Minerals
that can be
mined at a profit.
Uses of Minerals

http://www.minsocam.org/MSA/K12/uses/uses.html

http://www.emporia.edu/earthsci/amber/go336/talkingt/
The Copper Queen Mine in Bisbee, AZ
An Underground Halite Mine
Birthstones
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January
February
March
April
May
June
July
August
September
October
November
December
Garnet or Rose Quartz
Amethyst or Onyx
Aquamarine or Bloodstone
Diamond or Quartz Crystal
Emerald or Crysoprase
Alexandrite or Moonstone or Pearl
Ruby or Carnelian
Peridot or Sardonyx
Sapphire or Lapis
Opal or Tourmaline
Topaz or Citrine
Tanzanite, Zircon or Turquoise
History of Birthstones
 In early times, gemstones were believed to possess magical
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properties. Some minerals were thought to contain a force or
hold certain values and powers.
Tradition associates a gem with each sign of the zodiac based
on a color system. Color was thought to unleash the power
attributed to the stone.
The Roman, Arabic, Jewish, Polish, Russian and Italian
birthstone lists were all different.
In time, birthstones became associated with calendar months
rather than the zodiac.
And people began to select birthstones in colors other than the
original.
This list of birthstones, which is the one commonly used today,
was adopted in 1912 by the American National Association of
Jewelers, which later evolved into the Jewelers of America.
Mineral Compositions and
Groups
 Minerals are grouped based on their chemical
composition (the elements that make up the
minerals).
 Almost 98% of the Earth’s crust is made of
only 8 common elements (O, Si, Al, Fe, Ca,
Na, K, Mg).
Mineral Compositions and Groups
 Silicon (Si) and Oxygen (O) are the most common
elements in the Earth’s crust.
 Major groups are….(In order of size)
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Silicates (Si, O) (Largest rock forming group)
Carbonates (CO3)
Oxides (O3, O4)
Sulfides (SO4)
Sulfates (SO3)
Halides (F, Cl, I, Br)
Hydroxides (OH)2
Phosphates (PO3)
Native Elements (Au, Ag, Cu)
Mineral Compositions and Groups
Examples of Silicates
Hornblende
Examples of Silicates
Orthoclase Feldspar
Examples of Silicates
Plagioclase Feldspar
Carbonates
Sulfates
Halides
Native Element
Copper