Mineral A25

Image credit: S. Brande

Mineral A25 Resources and Instructions

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

Click image to enlarge in new browser tab

Image credit: Scott Brande

Ruler scale numbers in centimeters

Fragments Magnified

Size Scale: Paperclip 30 mm long, inside width about 5 mm.

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

Record results on Data Form

Backup on Youtube - Use Incognito

Reflected light

Size Scale: Paperclip 30 mm long, inside width about 5 mm.

Image credit: Scott Brande

Transmitted light

Size Scale: Paperclip 30 mm long, inside width about 5 mm.

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

Record results on Data Form

Backup on Youtube - Use Incognito

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

Record results on Data Form

Backup on Youtube - Use Incognito

Test Magnetism

Review property of magnetism

Watch the video demonstration below.

Alternative Observations - Your Choice

Record results on Data Form

Backup on Youtube - Use Incognito

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

Record results on Data Form

Backup on Youtube - Use Incognito

Test Electrical Conductance

Review property of electrical conductance

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

Alternative Observations - Your Choice

Record results on Data Form

Backup on Youtube - Use Incognito

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. 

Instructions for Studying Other Properties

Cleavage

Review properties of cleavage

Observe the close-up image. Is cleavage present?

Alternative Observations - Your Choice

If present, record results on Data Form under other properties

Ruler scale numbers in centimeters

Fragments broken from single crystal.

Breakage results in fragments showing numerous flat surfaces. Use chart to determine number of cleavage direction(s) and angle(s).

Image credit: Scott Brande

Conchoidal Fracture

Review properties of conchoidal fracture

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

Alternative Observations - Your Choice

If present, record results on Data Form under other properties

After observation, proceed to Crystal Form.

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

Record results on Data Form under other properties

Fragments broken from a single crystal.

Only if shape is recognizable use chart to determine crystal form.

Image credit: Scott Brande

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