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.
(http://facweb.bhc.edu/academics/science/harwoodr/geol101/labs/minerals/)
Problem
Can you identify a mineral from its properties?
Materials
Mineral samples
streak plate
Handlens
magnet
Penny
glass plate
Paper clip
SAFETY: WARNING!
Eye goggles MUST be worn at all times.
Keep hands away from face.
Report any spills to the teacher immediately.
Procedure (Methods)
1. Take one mineral sample out of the box and run it through it’s 1 – 4 physical
properties (Streak, Luster, How it Breaks, and Specific Gravity). Record
results in your data chart.
2. Test each sample with your hardness kit.
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 of all
acid. CAREFUL! Record if there was a reaction in the last column.
6. Show teacher data table for clearance to get a mystery sample.
7. Repeat steps 1-5 for your mineral sample and place data at the bottom of
the chart.
8. Using your data table, identify the mystery mineral.
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
NO GRAPH IS NEEDED FOR THIS LAB. Only questions need to be answered
in complete sentences. 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. How could you quickly tell halite from quartz?
7. How could you quickly tell calcite from quartz?
8. Identify the control group(s) and the experimental group for this lab
experiment.
9. What was your mystery mineral? Explain at least three observations that
helped you conclude this.
Conclusion
Make sure to summarize the entire lab (intro, methods, data, and results)
in this section.
Challenge:
Whether you are in 8th grade science or in a mineralogy department, there
are always more physical property tests compared to chemical property
tests for identification of minerals. Why do you think this is so? Explain
why you think this way.