Minerals and Rocks

What are Rocks Made of? All rocks are made of minerals Minerals can be identified by the way they look and by their physical characteristics

The Earth The earth’s crust is made of rocks Large rocks can be broken down into smaller rocks Smaller rocks can be broken down into the smallest particle called a mineral.

Did you know… The salt you sprinkle on your food is a mineral. The metal fork you use to eat with is made from minerals. The ceramic plate you eat from is made from minerals.

What is a Mineral? Minerals are natural, nonliving, solid crystals that make up rocks. Scientists have identified over 3,000 minerals Most of the rocks from the earth’s crust are made from a very small number of minerals.

Combinations of Minerals Most rocks are made from a different combinations of minerals. All over the world, each mineral has the same chemical make up no matter where it’s found. A grain of mineral quartz from a beach in Australia has the same chemicals as a piece of quartz found in the mountains of Australia.

Identifying Minerals Scientists identify minerals based on their physical characteristics. Color Luster Hardness Streak Cleavage

Color: Not mineral specific

Luster: How minerals reflect light Metallic Non-metallic

Hardness Moh’s Scale Hardness measures how easily it can be scratched

Streak: The color of the powder that a mineral leaves behind.

Cleavage Cleavage: areas of weakness along which minerals can break

3 Types of Rocks Sedimentary Rock Igneous Rock Metamorphic Rock

Lesson 2: How are Sedimentary Rocks Formed Water, ice, wind and gravity sweep bits of rock, soil, shells, sand and dead plant and animals matter from one place to another. This is called erosion The eroded material that settles on land or on the bottoms of lakes, rivers and oceans is called sediment

More and More Sediment… Over time… more and more layers of sand, soil, shells and rock lay on top of each other. New layers lay on top of old layers. The new layers press on top of the old layers. The weight of these layers pushes and sticks the rocks together. They harden and form Sedimentary Rocks.

Igneous Rock Comes from boiling hot lava (Molten) Your kitchen counter is made of Igneous Rock

Metamorphic Rock Morph = to change Metamorphic rock is rock that goes through changes from heat and pressure in the earth’s surface. Rocks that go through the Rock Cycle

Rock Cycle The recycling of old rock into new Heat, pressure, chemical reactions, weathering and erosion are some of the forces that drive the rock cycle All 3 rock types can change from one type into another Some rocks never go through the rock cycle Too deep in the earth’s surface Some rocks melt from the heat at the center of the earth

How Rocks Changed into Soil Over time, loose rocks on Earth’s surface take a beating. Water that drips into cracks in rock, freezes and thaws again and again. This makes the cracks larger and weakens the rock. Over time, this causes the rock to break apart. This is called weathering. Even the tallest mountains wear down over millions of years due to weathering.

How do Rocks Tell a Story Let’s read page 244 of the textbook to find out!

A scientist finds a fossil of a shell from a sea creature on a mountain range… What can you guess about the land around the fossil?