#36. To learn how to use mineral identification techniques to identify unknown minerals. To become more familiar with some common minerals. To review.

Mineral Mineral DetectiveDetective

LabLab#36

Purpose of LabPurpose of Lab• To learn how to use mineral identification

techniques to identify unknown minerals.

• To become more familiar with some common minerals.

• To review the parts of a laboratory experiment and report.

Lab TimelineLab Timeline• MONDAY: Introduction of Formal Lab, break into

pairs, write Title, Introduction, Hypothesis, Materials, Procedures, “Observations” column

• TUESDAY: In pairs, complete “Light Interaction”, “Smell,” and “Streak,”

• WEDNESDAY: Mohls Hardness Scale, Set up Solubility Tests

• THURSDAY: “Cleavage,” “Ice,” Finish observations for “Solubility”

• FRIDAY: Use information to identify minerals, write conclusion paragraph.

MONDAYMONDAY

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On a blank sheet of paper…On a blank sheet of paper…

• Your paper will have the following sections:– Title– Introduction Paragraph– Materials– Procedures ( just write “See Lab Instructions”)– Results (This will be the completed data table)– Modified Conclusion

Title and IntroductionTitle and Introduction• Name, date, period, #36 in the upper right hand

corner.• Write “Mineral Detective Lab” across the top.• On the first line, write “Partner(s): ________”• Skip a line and write “INTRODUCTION”• Please take 5 minutes to write ONE paragraph

that answers these questions…– What is the purpose of this lab?– Why is the information learned in this lab important?– Who could benefit from this information?

MaterialsMaterials

ProceduresProcedures• Skip a line and write “PROCEDURES.”• Write “See Lab Instructions.”

Test #1: ObservationsTest #1: Observations• Obtain 8 different mineral samples. They will

initially be identified using numbers 1-8.

• Match the mineral to its number using the very brief descriptions in the “Procedures.”

• Use a magnifying glass to carefully observe each mineral. Record a detailed description in your data table.

• Please focus on TEXTURE and LUSTER.

Test #2: Light Interaction TestTest #2: Light Interaction Test

• First, identify if each mineral is opaque, translucent, or transparent. Record your observations on the data table.

• Second, test all of your TRANSPARENT minerals for double refraction. – Do they cause any of the lines/letters to

appear double when placed on them and slowly rotated? Record your observations on the data table.

TUESDAYTUESDAY

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Test #6: Smell TestTest #6: Smell Test• Some minerals have very unique or distinctive

smells. It is easiest to smell a mineral if you have a fresh sample of its powder.

• Test the minerals in the following order: 8,7,6,5,4,3,2,1.

• Rub each mineral back and forth a few times on the streak plate. Immediately smell the powder.

• Record all observations in the data table.

Test #3: Streak TestTest #3: Streak Test• “Streak” is the color of the minerals

powder.

• Rub each mineral ONE OR TWO TIMES ONLY on the streak plate.

• Record the color of the powder that rubs off each mineral on the data table.

WEDNESDAYWEDNESDAY

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Test #4: HardnessTest #4: Hardness• Hardness describes how resistant a

mineral is to being scratched.

• A geologist named Freidrich Mohs developed a scale for rating the hardness of minerals: the higher the number, the harder the mineral.

Test #4: HardnessTest #4: Hardness• .

Test #4: HardnessTest #4: Hardness• Can it be scratched with a nail?

YES

NO

(These minerals are <5 )

(These minerals are >5)

Can it be scratched with a copper penny?

YES NO

(These are <3) (3-5)

Can it be scratched with a fingernail?

YES

NO

These are <2

These are between 2-3

Test #5: CleavageTest #5: Cleavage• Cleavage is a word used to describe how a mineral splits or

breaks.

• Observe the minerals to determine if they have…

– PERFECT CLEAVAGE: The broken surface is perfectly flat. Light reflects off when tilted back and forth.

– GOOD CLEAVAGE: Some of the broken surfaces appear perfectly flat. When the mineral is tilted back and forth in the light, there appears to be ONE position that reflects light very well.

– POOR/NO CLEAVAGE: The broken surfaces are irregular. Although the mineral might be shiny, none of the surfaces are perfectly flat.

THURSDAYTHURSDAY

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Test #3: Double Test #3: Double RefractionRefraction

• Lay each TRANSPARENT mineral across the straight and wavy lines on the instructions.

• Slowly rotate the mineral and see if any of the lines appear “double.”

• If yes: this mineral has “double refraction” and record this in your data table in the “Light Interaction” column.

Test #7 iceTest #7 ice• Work with another group to conserve

resources!

• Place 8 ice cubes on top of a paper towel.

• Place each mineral on top of an ice cube.

• Make observations for at least 10 minutes.

• When finished, dry each mineral and put back into tray.

Test #: SolubilityTest #: Solubility• This test will take 24 hours.

• This test will be completed as a class to conserve resources.

• We will place each mineral in water and in vinegar (weak acid) to see if they dissolve.

• We will record our observations tomorrow.

Time to Identify!Time to Identify!1. Mineral has good or perfect cleavage………Go to 2

Mineral has poor/no cleavage……………….Go to 52. Mineral is opaque…………………………Feldspar

Mineral is translucent or transparent………..Go to 33. Mineral has double refraction…………………Calcite

Mineral does NOT have double refraction……Go to 44. Mineral is soluble in water and acid……………Halite

Mineral is NOT soluble in water and acid………Mica5. Mineral is harder than 5 on Hardness scale……Go to 6

Mineral is softer than 5 on Hardness scale……Go to 76. Has greenish/black streak………………………Pyrite

Has no (colorless) streak…………………Rose Quartz7. Has rotten egg smell……………………………..Sulfur

Has no smell……………………………….Hematite

Conclusion ParagraphConclusion ParagraphPlease answer the following questions in your conclusion paragraph:

1.) What were the purpose(s) of this lab?2.) Give the name of each mineral, describe it, (3-4 words) and explain what feature(s) “give away” its identity.3.) Identify 3 sources of error in this lab, and how you could avoid these errors in the future.4.) Discuss two questions that you still have about minerals.

The end!The end!

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