Name:_____________________________ Date:_____________ Block:____
Lab Partner:___________________________
Mineral Identification LAB
Mineral Physical and Chemical Properties
Background
Determination of the actual chemical composition and crystalline structure
of a mineral is difficult without the proper equipment. In an introductory level lab
it is impossible for us to determine these two aspects of a mineral. Fortunately,
these two aspects determine a mineral's physical properties. How the atoms and
molecules are arranged and the strength of the bonding between the atoms result
in different physical properties for different minerals. While many minerals share
common physical properties, when all of a mineral's physical properties are
examined, it often results in a unique set of physical properties which can be used
to identify the mineral.
Citation:
Hardwood, Richard. "EARTH SCIENCE LAB Mineral Physical Properties and Identification." Richard Harwood's Courses Physical Geology
101. Black Hawk College, n.d. Web. 10 Oct. 2013. <facweb.bhc.edu/academics/science/>.
Problem:
How are minerals identified?
Hypothesis: (Read the background section above and use that information in your
hypothesis. Careful of format and paraphrase what you use.)
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Materials:
mineral samples
streak plate
handlens
magnet
penny
glass plate
paper clip/tack
HCl acid in dropper bottle
paper towel
data table
eye goggles
SAFETY:
Eye goggles MUST be worn at all times.
Keep hands away from face.
Report any spills to the teacher immediately.
Procedure:
1. Take one mineral sample out of the box and run it through its 1 – 5 physical
properties (Color, Streak, Luster, How it Breaks, and Specific Gravity).
Record results in your data chart.
2. Test each sample with your hardness kit (about ten known samples will be
given to you to run tests to get “baseline” data. – your control group).
3. Record the number on Mohs’ scale you feel it’s closest to, it can be between
two numbers.
4. Place the magnet next to the mineral and see if you feel any pull or observe
any movement.
5. Test the sample with a drop of HCl – be sure to wipe the mineral clean with a
paper towel. CAREFUL! Record if there was a reaction in the last column.
(bubbles, fizzing, etc.)
6. Show teacher data table for clearance to get a mystery sample.
7. Repeat steps 1-5 for your mystery mineral sample and place data at the
bottom of the chart.
8. Using your data table, identify the mystery mineral AFTER you have run
tests.
Mohs’ scale:
* Always make sure the scratch is real. Real scratches can’t be wiped off the
sample.*
IF…
Fingernail scratches it easily
1
Fingernail can barely scratch it
2
Fingernail cannot scratch it but penny can
3
Penny cannot scratch it but paperclip can
4
Paperclip can hardly scratch it but sample can’t scratch glass
5
Sample slightly scratches glass
6
Sample scratches glass easily
7
Mineral Identification Lab
Mineral Physical and Chemical Properties
Analysis: Graph your Mohs’ scale findings for all the known mineral samples
and include your “Mystery” sample as well.
Discussion:
Prove it or Lose it with your data/observations.
1. Explain the difference between a physical and chemical property.
2. What was the hardest mineral you had? What was the softest?
3. What mineral only had one direction of cleavage?
4. What mineral had an outstanding luster?
5. What mineral had the most misleading color compared to its streak?
(color is very different than streak outcome)
6. Identify the control group(s) and the experimental group for this lab
experiment. (independent variable is not knowing the name of the mineral
vs. knowing the name of the mineral before testing was conducted)
7. What was your mystery mineral? Explain at least three observations that
helped you conclude this.
Conclusion
Make sure to summarize the entire lab in this section. Use
data/observations as your support.
Challenge: Citations required in MLA format
1. Research some of the more “advanced” techniques to determine chemical
properties of minerals and explain your findings.
2. Research some of the “unusual” properties that some minerals may
display and identify the name of the mineral and the unique property is
has.