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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 (non-metallic 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 MINERALS• Black light on sample of Scapolite, which will fluoresce bright yellow
• 12 colored mineral samples in the kit
Yellow Fluorescence
Scapolite
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?