Minerals Properties Lab
Directions:
At each mineral property station complete the table and answer the question(s).Luster
| Mineral name | Chemical formula | Describe the luster |
|---|---|---|
| pyrite | FeS2 | |
| chalcedony | SiO2 | |
| limonite | Fe2O3 · H2O |
Which two of these have a nonmetallic luster? _____________________, __________________
Color
| Mineral name | Chemical formula | Describe the color |
|---|---|---|
| azurite | Cu2(CO3)2(OH)2 | |
| fluorite | CaF2 | |
| amphibole | CaNa(Mg or Fe)4(Al or Fe or Ti)3Si6O22(O or OH)2 |
Looking at the data of this table, make a prediction about the color of minerals containing copper.
Why isn't color a reliable identifier of minerals?
Streak
| Mineral name | Chemical formula | Describe the streak color |
|---|---|---|
| pyrite | FeS2 | |
| specular hematite | Fe2O3 |
What is surprising about the color of one of these streaks?
Cleavage / Fracture
Remember that when glass breaks it shows fracture.| Mineral name | Chemical formula | Does the mineral exhibit cleavage or fracture? |
|---|---|---|
| muscovite | KAl3Si3O10(OH)2 | |
| quartz | SiO2 | |
| calcite | CaCO3 |
Does table salt exhibit cleavage or fracture? ____________________
Heft
Rather than measure the actual specific gravity of the mineral samples, we will gauge the 'heft' or the relative weight of the samples.| Mineral name | Chemical formula | Heavier or lighter? |
|---|---|---|
| halite | NaCl | |
| galena | PbS |
How would looking at the chemical formula help you answer heavier or lighter?
Does halite exhibit cleavage or fracture? ____________________
Crystal Form
| Mineral name | Chemical formula | Does the mineral have regular (repeating pattern) or irregular crystalline shape? |
|---|---|---|
| goethite | HFeO2 | |
| malachite | Cu2CO3(OH)2 |
Does halite have a regular or irregular crystalline form? ____________________
Hardness
Remember: see if the mineral first scratches your fingernail, then if it scratches the penny, and finally the glass. With only three tools to use you will only be able to give a range of Mohs hardness.| Mineral name | Chemical formula | Range of Mohs Hardness numbers |
|---|---|---|
| mineral a | Al2O3 | |
| mineral b | Mg3Si4O10(OH)2 | |
| mineral c | CaF2 |
Mineral 'a' is used to make sandpaper and in a pure form is also called a ruby!
Special Properties
| Mineral name | Chemical formula | Describe a special property |
|---|---|---|
| magnetite | FexOy | |
| sulfur | S |
Why are there variables (x and y) in the chemical formula for magnetite?
What other minerals in this lab might have the same special property as magnetite? Why do you think this?