Mineral A06

Image credit: R. Weller, Cochise College.

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A21 A22 A23 A24

Mineral A06 Resources and Instructions

  • Observe properties in the image(s) and video snips.

  • Evaluate properties with knowledge of testing procedure and alternative results.

  • Record observations, conclusions on the Data Form or handout as instructed.

  • Identify the mineral by name.

  • Review answers and correct any errors after instructor provides answer key.

Unless otherwise noted, images are by Scott Brande.

Media Observable Properties for Identification

Observe Samples

Images are provided for most samples with approximate size scale information.

  • "Bulk" refers to "macro" (larger-sized) samples, in contrast to fragments best viewed under magnification.

  • Fragments were crushed from bulk samples, sieved through a 1-2 mm screen, and placed on a "micropaleontology" slide, used for mounting microfossils. Each square on the slide is about 4 mm wide.

Bulk

Click image to enlarge in new browser tab

Image credit: Scott Brande

Fragments Magnified

Size Scales: Image width about 20 mm. Each square about 4 mm on a side. End of paperclip about 5 mm inside width.

Image credit: Scott Brande

Test Luster

Review property of luster

Watch the video demonstration below and observe the close-up images.

Alternative Observations - Your Choice

    • metallic

    • non-metallic

Record results on Data Form

A06 fragments in reflected light; paperclip about 5 mm inside width.

Image credit: Scott Brande

A06 fragments in transmitted light; paperclip about 5 mm inside width.

Image credit: Scott Brande

Test Hardness

Watch the video demonstration below and observe the close-up image for evidence of an indented scratch.

Review property of hardness

Alternative Observations - Your Choice

    • harder than glass (H > 5.5)

    • softer than glass (H < 5.5)

Record results on Data Form

Image credit: Scott Brande

Test Streak

Watch the video demonstration below and observe the close-up image for evidence of a colored powder.

Review property of streak

Alternative Observations - Your Choice

    • gray scale: white gray black

    • colored scale: red-ish orange-ish yellow-ish green-ish blue-ish purple-ish

Record results on Data Form

A06

Image credit: Scott Brande

Test Magnetism

Review property of magnetism

Watch the video demonstration below.

Alternative Observations - Your Choice

    • magnetic

    • not magnetic

Record results on Data Form

Test Acid Reaction

Review property of acid reaction

Watch the video demonstration below and study the image for evidence of a reaction.

Alternative Observations - Your Choice

    • reacts to acid

    • no reaction to acid

Record results on Data Form

Image credit: Scott Brande

Test Electrical Conductance

Review property of electrical conductance

Watch the video demonstration below and observe the close-up image.

Alternative Observations - Your Choice

    • conducts electricity

    • doesn't conduct electricity

Record results on Data Form

Observe Other Properties

Limitations of Observations

For various reasons, student-grade mineral samples may not exhibit all properties listed in the Data Form, making mineral identification more challenging.

  • Some properties may be present, but not well-developed (e.g., cleavage)

  • Some samples may be aggregates composed of microscopic crystals, making observation of a property (e.g., cleavage, conchoidal fracture, crystal form) impossible

  • Some samples may not be composed of the pure compound, thus making recognition of the target sample property more difficult.

Instructions for Studying Other Properties

  • Don't spend a lot of time trying to observe, recognize, describe, and record these properties - they may not be well- developed.

  • When a property appears to be well-developed, look back and forth between the mineral sample and reference illustrations (e.g., cleavage) to make visual comparisons. Repetitive practice will help you to integrate information, and you will develop an increasing familiarity that speeds your study.

  • Use your textbook or other references for more extended explanations and additional illustrations.

Cleavage

Review properties of cleavage

Observe the close-up image. Is cleavage present?

Alternative Observations - Your Choice

    • repetitive (multiple) cleavage (planar) surfaces are present - identify pattern of flat, reflective surfaces by comparison to illustration below

    • cleavage (planar) surfaces not present or cannot be determined - proceed to observation for conchoidal fracture (below)

If present, record results on Data Form under other properties

A06 Fragments broken from single crystal.

Cleavage/fracture prevents breakage into ideal crystal form. Can't determine ideal single crystal form for this mineral from fragments.

Image credit: Scott Brande

Conchoidal Fracture

Review properties of conchoidal fracture

Observe the close-up image. Is conchoidal fracture present?

Alternative Observations - Your Choice

    • conchoidal fracture cannot be determined

    • conchoidal fracture is present

    • conchoidal fracture not present

If present, record results on Data Form under other properties

After observation, proceed to Crystal Form.

A06 Fragments broken from single crystal.

Is conchoidal fracture present? Examine pattern of light reflections from surfaces of broken fragments.

Image credit: Scott Brande

Crystal Form(s)

Review properties of crystal form

Observe the close-up image.

Alternative Observations - Your Choices

    • geometric form may be irregular and difficult to interpret

    • geometric form is recognizable - compare to property chart (below)

Record results on Data Form under other properties

A06 Single crystals.

Compare face shape, corner / side angles, and overall solid form to chart for identifying the form of this crystal.

Image credit: Scott Brande