Lab 2 Exercises
The exercises below will guide you through the mineral samples in Mineral Kits 1 and 2. Review the physical properties of minerals presented in Chapter 2.3 before you begin these exercises. You may wish to consult the mineral identification tables at the back of this manual as you complete the exercises below.
Part I: Cleavage and Fracture
The minerals in this part include a mix of silicate and non-silicate minerals found in Mineral Kits 1 and 2.
1. Do the following samples exhibit cleavage or fracture? If the sample exhibits cleavage, specify the number of cleavage planes and approximate angle between them.
| Sample | M226S | M225S | M1S | M251S | M111S | M223S | M131S |
| Cleavage or fracture |
|
2. What is the difference between a crystal face and a cleavage plane?
3. Look at sample M202(S). This is a good example of a mineral with 2 cleavages at almost right angles to each other. Select two other samples that also demonstrate this type of cleavage.
4. Now select a sample which also appears to have a least two cleavages but with the cleavage surfaces oblique (at some angle other than 90°) to each other.
5. Which sample has one (perfect) cleavage only?
6. Look at the fractured surface of sample M225. Try to describe this surface (rough? curved? splintery? etc.). This is an example of conchoidal fracture. Does this sample exhibit any cleavage?
7. What other sample also exhibits conchoidal fracture?
Part II: Non-silicate Minerals
Certain physical properties are diagnostic for a particular mineral. These diagnostic properties will help you distinguish a particular mineral. The questions below will help you identify these diagnostic properties. Remember: you must be able to identify all the physical properties of each mineral, not just the diagnostic properties. You should also know the group to which each mineral belongs (e.g., sulphides, oxides).
Mineral Group: Native Elements
| Sample M21 | Mineral name: |
1. Does this mineral exhibit cleavage? If yes, describe the cleavage:
2. What is the approximate hardness of the sample on the Mohs scale of hardness?
3. What is the specific gravity of the sample (high, medium or low)?
4. Describe the lustre of this mineral:
5. Describe the streak:
6. What is a diagnostic property of graphite?
Mineral Group: Oxides
| Sample M11/M12 | Mineral name: |
| Sample M51/M52 | Mineral name: |
| Sample M53 | Mineral name: |
1. Do any of these samples exhibit cleavage?
2. If yes, which one? Describe the cleavage:
3. Looking at samples M51/52 and M53, what is the lustre of each sample?
| Sample M51/M52 | Lustre: |
| Sample M53 | Lustre: |
4. Compare the streak of each sample. Describe what you see:
5. Do any of the samples attract a magnet? Which one?
6. What is the diagnostic property of magnetite?
7. What is the diagnostic property of hematite?
Mineral Group: Carbonates
| Sample M251 | Mineral name: |
1. Does this mineral exhibit cleavage? If so, describe the cleavage:
2. What is the approximate hardnes