BELL WORK
Complete the Thursday Bell Work question.
If you finish early, read or review your minerals notes.
OBJECTIVES
GLE 0707.7.1 Describe the physical properties of minerals
Can I use the properties of minerals to determine the
identity of an unknown mineral?
SAFETY CONSIDERATIONS
Eye protection: You must wear goggles for the acid test.
VOCABULARY REVIEW
• Mineral
• Luster
• Streak
• Hardness
• Moh’s Scale
• Cleavage
HOW DO SCIENTISTS TELL
MINERALS APART?
Our “unknown” minerals: talc, rose quartz, smoky quartz,
halite, galena, magnetite, graphite, feldspar, calcite,
gypsum)
Today, as geologists, you will investigate the 2 minerals
assigned to you, record data about their properties and
then be able to identify the minerals.
TEST #1 & DEMO: STREAK TEST
• Streak Test
• 2 minerals that are both
quartz (pink Rose quartz and
white Milky quartz). The
different colors are from
different impurities.
• The minerals will have the
same streak test. The mark
left on the tile is the mineral’s
streak.
• Determine the streak of a
mineral simply by dragging
the mineral across the black
streak plate ONCE.
TEST #1: STREAK TEST
• Gently stroke the edge
of the mineral across
the white streak plate.
• Record the color that
the streak produces. If
no streak appears,
record "not visible” on
the investigation sheet.
• Make only one streak
per mineral since the
tiles and minerals are
needed for other
classes.
TEST #2: HARDNESS TEST
• Moh’s Scale
• Use the testers in the following
order to test the hardness of the
mineral:
•
•
•
•
Piece of glass
Piece of iron
Piece of copper
Fingernail
• Determine the Mohs hardness of
the mineral by finding the
HARDEST (i.e. the FIRST) tester
that the mineral will scratch.
Circle that tester & its
corresponding hardness on the
observation sheet.
• NOTE: Keep glass plates flat on
the tables or they will snap
TEST #3: CLEAVAGE AND FRACTURE
TEST
• Cleavage
• If the mineral cleaves,
you will observe flat
surfaces.
• Muscovite demo
(sheets)
• If a mineral fractures, it
breaks unevenly along
curved or irregular
surfaces (see
hematite).
• Not all cleavage is as
smooth as muscovite.
Cleaving minerals
(muscovite)
Fracturing minerals
(hematite)
TEST #4: LUSTER TEST
• Aluminum foil is shiny
and reflects light well
(metallic luster)
• Glass is shiny, but does
not reflect (non-metallic
luster - Glassy)
• Wood is dull (nonmetallic luster - Dull)
• Bead container is pearly
(non-metallic luster Pearly)
• Hand lenses may be
needed to see luster.
TEST #5: MAGNETISM TEST
• Touch the mineral with the
magnet.
• If the mineral is attracted to
a magnet, the mineral is
magnetic.
• If there is an attraction,
circle yes
• If there is no attraction,
circle no
DETERMINE UNKNOWN
MINERAL
• After performing all five tests, you will determine the
name of your unknown mineral using properties of
minerals handout
SPECIAL PROPERTIES: ACID TEST
• If a mineral is a carbonate, it will fizz
with acid.
• We are performing acid test on a
ROCK marble (emphasize that it is not
a mineral but made up of minerals).
• Observe and record your
observations.
SPECIAL PROPERTIES: ACID TEST
• Put 1 drop on the marble and observe
what happens. You may need to use
your magnifier.
• What mineral do you think makes up
marble?
• Do you know of any other rocks that
react similarly with acid? (How does
acid rain affect rocks?)
OPTIONAL: SPECIAL PROPERTIES—
FLUORESCENCE OF MINERALS AND COLOR OF
Scapolite MINERALS
• Black light on sample of
Scapolite, which will
fluoresce bright yellow
Yellow
Fluorescence
• 12 colored mineral
samples in the kit
Colored Minerals
EXIT TICKET & REFLECTION
1. For what would you use the Moh’s
scale?
2. Name three tests that scientists use to
identify minerals.
3. What is the difference between mineral
color and streak?
Reflect:
On a scale of 1-10, how well do you
understand mineral identification? What do
you need in the next lesson to feel more
knowledgeable about mineral
identification?