Earth Flashcards
What are rocks made of
Minerals
What are minerals
Naturally occurring Distinct chemical composition Distinct physical properties Crystalline structure Inorganic (not living)
What is a gemstone
Usually a mineral, one that formed crystals then cut and polished to be made jewelry
How do you tell what a mineral is
Lustre Hardness Cleavage/Fracture Streak Colour
Lustre
Shiny or dull
Metallic or non-metallic
Colour
One best describes the minerals appearance
Streak
The colour of the powder of the mineral, can be a different colour.
(Making a streak with the mineral on a white, dull surface like paper)
Cleavage or fracture
The way the mineral breaks apart
Fracture is rough and jagged break
Cleavage is a smooth flat surface broken
Hardness
Hard or soft
Use teh Moh’s hardness scale (scratch test)
1 is the softest and 10 is the hardest
Igneous rocks
formed by melting and cooling of lava or magma Contain crystals Intrusive rocks form below the surface Extrusive rocks form above the surface Granite, basalt, gabbre
Sedimentary rocks
Formed when sediments (small bits) settle and form layers
Often contain fossils
Sediments are compacted and cemented together
Sandstone, limestone, conglomerate
Metamorphic rocks
Formed below earths surface
Heat and pressure cause existing rock to transform
Marble, Quartzite, Slate
Erosion
Movement of soil, rocks and minerals from one place to another
Gradual such as glaciers
Sudden change such as flash floods or earthquakes
What are the 4 agents of erosion
- Gravity
- Glaciers
- Wind
- Moving water
Weathering
The breaking down of rocks into smaller rocks and sediment
The 3 types of weathering
- Mechanical
- Chemical
- Biological