Classifying Minerals
How do geologists classify minerals?
There are 1000s of minerals!
Geologists need a way to keep track of all these minerals!
One way you can classify minerals is by how hard they are.
Can you scratch the mineral with a fingernail? Penny? (Construction) Nail? “File”? Diamond?
Fingernail: Bierenard - Own work, CC BY-SA 4.0, wikimedia commons; Penny:wikipedia public domain; nail algotrunemen openclipart.com
Classifying Minerals: Color
Color is not always reliable - but can be used to help classify
“Azurite” is a blue mineral
Pure Quartz is clear (left), but small impurities turn it into other colors!
Clear quratz: JJ Harrison Own work, CC BY-SA 2.5; yellow quartz: By Jarno from Rotterdam, Netherlands; Pink quartz: By Rob Lavinsky, iRocks.com – CC-BY-SA-3.0, all via wikimedia commons
Classifying Minerals: Streak
When you scratch a “tile” with minerals they will leave a streak - this streak can be a different color than the mineral.
By Ra'ike (see also: de:Benutzer:Ra'ike) - Own work, CC BY-SA 3.0, wikimedia commons
Classifying Minerals: Luster
Does your mineral look shiny or reflect light?
See photo attribute on next slide
Different types of luster
Silky: By Ra'ike (see also: de:Benutzer:Ra'ike) - Own work, CC BY 2.5; Pearly; By Luis Miguel Bugallo Sánchez wikimedia commons;Greasy: By Ra'ike - Own work, CC BY-SA 3.0; Metallic: JJ Harrison - Own work, CC BY-SA 3.0; Dull: public domain
“silky”
“pearly”
“metallic”
“greasy”
“dull”
Classifying Minerals: Chemical
Does your mineral bubble
when placed in vinegar?
If so it probably contains something called “carbonate”. Some chalks have carbonate and will react in vinegar like certain rocks!
See photo attribute on previous slide
Discuss with your partner the different ways you can classify minerals