RL Hanna
Geology
Minerals ID Properties
Read through the lab manual exercise info on Minerals & Mineral Identification.
Read through the lecture textbook section on the Physical Properties of Minerals
1. Use your lab manual, your lecture textbook, Geode on the Mastering Geology website, and the
internet to answer the following questions:
2. Explain mineral cleavage. DO NOT just copy a definition from somewhere… construct a good
explanation that you can use to explain mineral cleavage to anyone who is not taking this class.
3. Explain mineral fracture. DO NOT just copy a definition from somewhere… construct a good
explanation that you can use to explain mineral fracture to anyone who is not taking this class.
4. Explain crystal habit. DO NOT just copy a definition from somewhere… construct a good
explanation that you can use to explain crystal habit to anyone who is not taking this class.
5. Explain hornblende’s cleavages. DO NOT just copy a definition from somewhere… construct a
good explanation that you can use to explain mineral hornblende’s cleavages to anyone who is not
taking this class.
6. Familiarize yourself with the shapes and names of the crystal forms – see the chart in your AGI
lab manual (e.g., dodecahedral, etc.)
7. Familiarize yourself with the # of cleavage directions and shapes – see the chart in your AGI lab
manual.
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RL Hanna
Geology
8. What shape are each of these crystals?
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bladed
cubic
dodecahedral
hexagonal prisms
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octahedral
pyramidal
pyritohedron
rhombohedral
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scalenohedral
tabular
tetrahedral
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RL Hanna
Geology
9. What cleavage is shown by each mineral?
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no cleavage
one-direction; perfect: (basal)
2-directions at 90° (or very close to 90°)
2-directions NOT at 90°
2-directions (at 60° and 120°)
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3-directions at 90°
3-directions NOT at 90°
4 directions
6 directions
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RL Hanna
Geology
10. CLEAVAGE
• a shape that a mineral grows into
• color of powder
• hardness - not scratched by fingernail and does not scratch glass
• hardness - scratched by fingernail
• hardness - scratches glass
• reflectivity/"shinyness"
• weight compared to size
• when a mineral breaks along a flat surface
• when a mineral breaks unevenly
11. SPECIFIC GRAVITY
• a shape that a mineral grows into
• color of powder
• hardness - not scratched by fingernail and does not scratch glass
• hardness - scratched by fingernail
• hardness - scratches glass
• reflectivity/"shinyness"
• weight compared to size
• when a mineral breaks along a flat surface
• when a mineral breaks unevenly
12. FRACTURE
• a shape that a mineral grows into
• color of powder
• hardness - not scratched by fingernail and does not scratch glass
• hardness - scratched by fingernail
• hardness - scratches glass
• reflectivity/"shinyness"
• weight compared to size
• when a mineral breaks along a flat surface
• when a mineral breaks unevenly
13. LUSTER
• a shape that a mineral grows into
• color of powder
• hardness - not scratched by fingernail and does not scratch glass
• hardness - scratched by fingernail
• hardness - scratches glass
• reflectivity/"shinyness"
• weight compared to size
• when a mineral breaks along a flat surface
• when a mineral breaks unevenly
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RL Hanna
Geology
14. STREAK
• a shape that a mineral grows into
• color of powder
• hardness - not scratched by fingernail and does not scratch glass
• hardness - scratched by fingernail
• hardness - scratches glass
• reflectivity/"shinyness"
• weight compared to size
• when a mineral breaks along a flat surface
• when a mineral breaks unevenly
Crystal Habit: How many sides?
15. CUBIC HABIT?
16. DODECAHEDRAL HABIT?
17. OCTOHEDRAL HABIT?
18. RHOMBOHEDRAL HABIT?
Crystal Cleavage: How many directions?
19. CUBIC CLEAVAGE?
20. DODECAHEDRAL CLEAVAGE?
21. OCTOHEDRAL CLEAVAGE?
22. RHOMBOHEDRAL CLEAVAGE?
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1 side
2 sides
3 sides
4 sides
5 sides
6 sides
7 sides
8 sides
9 sides
10 sides
11 sides
12 sides
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1 direction
2 directions
3 directions
4 directions
5 directions
6 directions
7 directions
8 directions
9 directions
10 directions
11 directions
12 directions
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