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?