Download Mineral Identification Lab

adapted from 1994 WARD’S Natural Science Establishment, Inc.
Mineral Identification Lab
Background: The Earth’s crust is composed of a wide variety of rocks composed of
minerals which are fascinating to collect and identify. More importantly, understanding
minerals and their properties is critical to the search for important industrial raw
materials used in many of the products we’ve come to rely on in everyday life. What is a
mineral, and how do we distinguish one type from another? Minerals are inorganic,
naturally-occurring, crystalline solids with a definite chemical composition and a highly
ordered arrangement of elements in a distinct atomic pattern. This orderly structure
creates a series of physical and chemical properties that are constant for each mineral.
Minerals can, therefore, be readily identified and classified by checking these specific
properties. Some properties can be determined by basic observation, while others can
be easily tested with simple tools. Among these characteristic properties are mineral
color, luster, streak color, hardness, cleavage/fracture, and density (specific gravity).
Purpose: What characteristics do minerals have?
Hypothesis: None – just figure out the minerals…
Materials & Procedure: Listen to directions, fill in the DT, & answer conclusion Qs.
Data:
Data Table 1: Mineral Characteristics and Identification
Characteristic Sample Sample Sample Sample Sample Sample Sample Sample
1
2
3
4
5
6
7
8
Color
Luster
(metallic or
non-metallic)
Streak
Color
Hardness
(Moh’s Scale)
Cleavage
or
Fracture
Mineral ID &
Chemical
Formula
Density g/cm3
(aka Specific
Gravity)
Special
Properties
adapted from 1994 WARD’S Natural Science Establishment, Inc.
Mineral Identification Lab
Conclusion:
Part 1: Complete when done observing all 8 mineral samples.
1. Define what is meant by streak color.
2. Tell which of the mineral samples (by name) you tested had a streak color that was
dramatically different from the sample’s natural color.
3. Tell the mineral samples (by name) in your set that clearly display good cleavage.
4. Tell the mineral samples (by name) in your set that have metallic luster.
5. Which of the mineral samples fizzed and bubbled when tested with hydrochloric
acid? What does this reaction indicate the presence of?
Part 2: When you and your partner have completed Part 1, compare the test results in
your Mineral Data Table with information listed in the Mineral Identification Key in
Appendix B, pgs. 806-807 of your Earth Science Book. Identify your 8 samples based
on your test data and enter your results and densities (specific gravities) in your table.
6. According to the Mineral Identification Key, tell two characteristic properties that
would distinguish galena and graphite, assuming that both minerals are
approximately the same color.
7. Tell the name of the softest mineral sample from the lab listed in the Mineral
Identification Key.
8. Tell the name of the hardest mineral sample from the lab listed in the Mineral
Identification Key. What does this hardness mean it can do?
9. Which tests were the most useful in selecting the minerals that fit the description for
each specimen?
10. Describe other tests that might be useful in positively identifying your specimens.
11. In general, most metallic minerals have an average density (specific gravity) of
5.0 g/cm3. Non-metallic minerals average only around 2.7 g/cm3. On the basis of
these averages & the information collected in your data table, which of your samples
would you classify as metallic? Non-metallic? What does this mean for graphite?