Minerals
• What in this classroom is made from
minerals?
Beryllium in computers, cell phones and
emeralds
Chromite-chrome faucets
Feldspar in the glass
Lithium-electronics batteries
Minerals are found in rocks,
smaller sediments and dissolved
in water
If you find a mineral, how do you know
what it is?
Can you tell by looking, if this is gold or “fool’s
gold”?
Can you tell if it’s diamond or quartz?
Focus Question
• What are the minerals in your box and how do
you know?
• Write down your predictions in your science
notebook.
I predict mineral 1 is…………
I predict mineral 2 is………….
I predict mineral 3 is ………….
You can’t tell just by looking!
You need evidence from a variety of tests to
identify a mineral.
These tests identify the properties of a mineral.
A property is an observable characteristic of
matter.
Color
• Describe the color.
Streak
• The color of the mineral in powdered form.
• Turn the mineral into a powder by rubbing it
against the porcelain tile.
Luster
• Luster is how light reflects off a mineral. It can
be metallic (shiny) or non-metallic (not shiny)
Metallic luster:
Non-metallic luster
• Can be glassy
• Can be a variety of other things, dull, greasy,
but we will just call them “non-metallic”
Give it a try
Describe the color, streak, luster and of the 8
minerals in your box.
What did you notice?
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Share data for streak
Share data for luster
Do we agree?
Was the color always the same as the streak?
Anything else that you observed?
Questions that came up?
How a mineral breaks: cleavage or
fracture?
• Cleavage-When the mineral breaks it will
break along parallel planes. You will see
repeating patterns:
How a mineral breaks
• Fracture-it will irregularly break with out a
definite shape
Don’t break it
• Look at the edges and predict whether or not
your minerals have cleavage or fracture.
Share data for cleavage vs. Fracture
• Mineral 1, fracture
mineral 2: Cleavage
Mineral 3: Fracture
Mineral 4: Cleavage
Mineral 5: fracture
Mineral 6: Cleavage
Mineral 7: Cleavage
Mineral 8: cleavage
Hardness p. 2 of lab
• Minerals are rated on a hardness scale of 1-10.
1 is the softest (talc that makes talcum
powder). 10 is the hardest (diamond)
• Testing tools have a hardness rating see p. 2 in
lab
• The harder item scratches the softer item.
• REPLACE NAIL WITH PAPERCLIP IN LAB
DIRECTIONS
• Read p. 2 and try answering the questions.
Try #1 We will go through this one step at a time.
• Scratch the mineral with your fingernail.
• Does it get scratched? Then it is _______than your
fingernail. Give it a hardness of 2.
• Does it resist getting scratched? Then it is ____________
than your fingernail.
• If it is too hard to be scratched, move to the next harder
tool, the copper strip or penny.
• Scratch the copper strip with your mineral. If it doesn’t
scratch it is 3, if it does it is greater than 3 and you will
move to a harder tool, paperclip.
• Does the paperclip scratch the mineral? Then the mineral is
softer than the paperclip and it is between 4-5. If it resists
being scratched it is harder than 5.5. Go to the glass.
• If if doesn’t scratch the glass if is 5-6. If it scratches the
glass it is greater than 6.
• If if doesn’t leave a streak on the streak plate it is harder
than 7.
Let’s try together
• Mineral _____together
• Rest of minerals by yourself. Share materials
with you partner. But, make sure you get a
chance yourself!
• Share results
Share results
• #1: 6-8; #2: 2-4; #3: 5-7; #4:1-2; #5: 5-7
#6: 2-4 #7: 5-7 #8: 1-3
• In earth science, hardness is defined as the
resistance to being scratched.
• Sometimes you can use minerals instead of
tools. Try the bottom of p. 2
Chemical Reactions
• In a chemical reaction something new such as
a gas is produced.
• This is different than a phase change, when
you heat something up it turns to a gas.
• Put Hydrochloric acid on a rock, see if gas is
produced.
• If you get a gas, a chemical reaction occurred.
If not, no reaction.
Safety rules
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You must wear goggles
Put your mineral in a tray with a paper towel.
Use only one-two drops.
Dry your minerals off with the paper towel.
Member number _____ get paper towel and
throw it away.
• Member number _____ is in charge of goggles.
• You may not take off goggles until I have collected
your Hydrochloric acid.
Complete the chemical tests as a group
• What are your results?
Can you identify your minerals?
Use the mineral identification key to match
your mystery mineral with the mineral that
has the most similar properties.
Data Analysis
• We now need to analyze our results to see
what they show/tell us.
• On a piece of loose-leaf, answer the following
questions in complete sentences.
1. Which property was most useful to ID the
rocks? WHY?
2. Which property could be most misleading to
the identification of a rock? WHY?
Conclusion
• Complete your concluding paragraph by
answering the following questions:
1. What was the purpose of this laboratory
experiment?
2. What properties of minerals did you use to
identify the rocks? Explain them!
3. Possible errors?
4. What additional question do you have about
identifying mystery rocks?