MINERALS Flashcards
1
Q
Minerals
A
- naturally occurring
- inorganic
- known chemical composition
- fixed atomic structure
- rocks are aggregates of minerals
2
Q
Colour
A
- can be diagnostic (e.g malachite - green)
- not very useful as colour is influenced by impurities
3
Q
Streak
A
- colour of the mineral when powdered
- rub mineral on streak plate to see
- e.g gold looks like pyrite, gold has gold streak, pyrite has black streak
- doesn’t work on hard minerals
4
Q
Lustre
A
- shinyness/reflectiveness of mineral
- metallic, glassy, dull, etc
5
Q
Cleavage
A
- ability to split mineral (along cleavage plate)
- e.g mica has perfect cleavage in one plane
6
Q
Fracture
A
- non-cleavage break, uneven
- e.g conchoidal fracture looks like a shell
7
Q
Hardness
A
- mohs scale
1. Talc
2. Gypsum
3. Calcite
4. Fluorite
5. Apatite
6. Feldspar
7. Quartz
8. Topaz
9. Corundum
10. Diamond - 2-3 - fingernail
- 3-4 - copper coin
- 5 - glass
- 6 - hardened nail
8
Q
Density
A
- mass(g) / volume(cm³)
- calculate with a eureka can (displaced water = volume)
- e.g galena and barite are denser than average
9
Q
Other properties
A
- magnetic - e.g magnetite
- taste - e.g halite (salt)
- reacts with dilute HCl - e.g calcite fizzes, galena smells of rotten egg
- flexible - e.g mica
