ROCKS Planet Earth – Topic 2
ROCKS
Planet Earth – Topic 2
Minerals are the “building blocks” of rocksThere are more than 3,500 different
minerals on EarthBut, most rocks are made up of the
same 5 minerals:CalciteQuartzFeldsparMicaHornblende
Rocks vs. Minerals
ColorLustre Streak CleavageFractureHardness
Properties of Rocks
Moh’s Hardness Scale
1. Igneous Rocks Formed when hot, molten rock
(magma) cools and hardens Intrusive rocks form under the Earth’s
crust as magma cools Extrusive rocks form when lava cools and
hardens on the Earth’s crust Basalt is the most common type of
igneous rock
The 3 Types of Rocks
The Devil’s Tower
2. Sedimentary Rocks Formed when small pieces of rock are
carried by water or wind and settle onto the bottom of rivers, lakes, or land
As the layers pile on, time and pressure cause the layers to harden
The bottom layer is the oldest, and the top layer is the youngest
The 3 Types of Rocks
Sandstone
3. Metamorphic Rocks Rocks that have been changed These rocks were once igneous or
sedimentary, but the intense heat and pressure within the Earth changes the appearance of the rock
Marble is a common example of this type of rock
The 3 Types of Rocks
Marble and Quartzite
Turn to page 382 in your textbook, and look over the “Rock Summary Table” on that page
Draw the charts seen on page 383 in your notebook and use the rocks and tools provided to determine the type of rocks you analyze
Can You Tell the Difference?
Just like the way you and I recycle bottles, paper, and other wastes; the Earth recycles too!
The Earth recycles rocks A rock will undergo several
changes over time, and can fit into each rock type over time
The Rock Cycle
The Rock Cycle
Cooling, Erosion, Pressure, Intense Heat and Pressure, Melting