1. Minerals, Rocks, and The Rock Cycle
22.2, 22.3

2. Minerals and Rocks
A rock is a solid combination of minerals or mineral materials
A mineral is:
Inorganic (not from living things)
Solid
Has a crystalline structure
Characteristic chemical composition
Building blocks of rocks

3. Classification Minerals are classified by:
Crystal structure; their geometric shape
Color
Streak; color of its powder
Luster; ability to reflect light
Density; mass/volume
Hardness; ability to avoid scratching
Fracture; how it breaks
Cleavage; type of fracture
Others include ability to dissolve in acid, electrical properties, light refraction

4. Mohs Hardness Scale Talc Gypsum Calcite Fluorite Apatite Orthoclase
Quartz
Topaz
Corundum
Diamond

6. Igneous Rocks Form from magma
Magma that flows from volcanoes is called lava
Form when rock cools and solidifies
Intrusive rocks cool inside the Earth, cool slowly making large crystals
Extrusive rocks cool outside the Earth, cool rapidly

7. Intrusive Rocks Gabbro, Granite

8. Extrusive Rocks Obsidian, Basalt

9. Sedimentary Rock
Weathering breaks down the Earth into smaller pieces called sediment
Sediment comes from living organisms or rock
Sedimentary rocks form over time when sediment is squeezed and cemented together
Pressure causes the sediments to compress

10. Clastic Rock
Sedimentary rock that forms when other rocks break and fracture
Classified by size of particle which range from pebble size to boulders
Conglomerate rocks contain gravel and pebbles and pieces are rounded
Breccia is composed of sharp rock fragments

11. Conglomerate, left Breccia, right

12. Chemical Rock Form when rock precipitates out of a solution
Rain falls and dissolves rock, the minerals are carried in streams, eventually the streams can evaporate leaving new rock behind, or the sediments settle forming limestone
Typically found in dry lake beds or caves

13. Limestone in Lehmann Caves, Great Basin National Park, Eastern Nevada

14. Organic Rock Form when organisms die
Shells and skeletons compress under pressure and cement to form rock

15. Chalk Bluff
Along Truckee River
Reno, Nevada

16. Limestone, formed on ocean floor, left
Limestone in White
Cliffs of Dover,
England, right

17. Metamorphic Rock Greek for “change form”
Transformed by heat, pressure, chemical reactions, and time
Metamorphism can change the mineral content as new rocks become embedded in the new rock
Change the texture and lead to layers
Foliated rocks look like strips because the layers are parallel

18. Gneiss Schist

19. Rock Type Quiz

20. The Rock Cycle

21. Essential Questions
What are the ten most common properties that minerals are classified by?
What are three groups into which rocks are classified?
What are the two ways igneous rocks can form?
What are the three groups of sedimentary rocks called?
How are metamorphic rocks formed?

22. References Gabbro image www.k12.nf.ca
Granite image marlimillerphoto.com
Obsidian, limestone images
Basalt image
Conglomerate
Breccia flexiblelearning.auckland.a...
Lehmann Caves blog.roadtrippers.com
White Cliffs
Metamorphic rock