ROCKS

Minerals are the “building blocks” of rocks There are more than 3,500 different minerals on Earth But, most rocks are made up of the same 5 minerals: Calcite Quartz Feldspar Mica Hornblende

Color Lustre Streak Cleavage Fracture Hardness

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

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

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

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

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

Cooling, Erosion, Pressure, Intense Heat and Pressure, Melting