1. Chapter 2, Lesson 2, Minerals and Rocks

2. Chapter 2, Lesson 2, Minerals and Rocks Slide 1
*Main Idea
-What is Earth made of?
*The solid Earth is made of minerals and rocks.
-The solid part of Earth is made up of minerals and rocks.
-People use them to build homes and roads.
-They are broken down in soil to grow food, and used as jewelry because of their beauty.
-Scientists have identified 3,800 distinct minerals, but there are only about 30 common ones.

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-What is Earth made of? continued
-Minerals form when crystals grow in nature.
-They can grow in melted rock material or from material dissolved in water.

4. Chapter 2, Lesson 2, Rocks and Minerals Slide 3
*What is a mineral?
*A mineral is a naturally occurring, generally inorganic solid that has a crystal structure and a definite chemical composition.
*Minerals have the following properties:
Naturally Occurring- To be considered a mineral, a substance must be found in the natural world. For example, diamonds mined from Earth are minerals, but synthetic diamonds made in laboratories are not.
Generally Inorganic-Most minerals are formed by processes that do not involve living things. There are some minerals made by living things, such as the mineral apatite which can be found in your bones and teeth.

5. Chapter 2, Lesson 2, Rocks and Minerals Slide 4
What is a mineral?
3. Solid-Substances that are liquids or gases are not considered minerals. If a mineral is heated and melted into a liquid, it is not a mineral.
4. Crystal Structure -The atoms in a mineral are arranged in orderly, repeating patterns. The regular atomic pattern is called a crystal structure.
5. Definite Composition-A mineral is made of specific elements that are in specific proportions. For example, the mineral quartz is made up of two oxygen atoms for every silicon atom.

6. Chapter 2, Lesson 2, Minerals and Rocks Slide 5
-What are physical properties of minerals?
-You can tell one mineral from another by its physical properties.
-They are characteristics that can be observed or measured without changing the identity of the mineral.
-You can identify minerals by:
Hardness-You can test the hardness of a mineral by observing how easily it is scratched. An Austrian scientist, Friedrich Mohs developed a hardness scale of 1 to 10 with the hardest mineral, diamond, being a 10 and the softest, talc, being a one.

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Mohs Scale of hardness

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-What are Physical properties of minerals? Continued
Color-A mineral’s color can sometimes be used to help identify it. The mineral malachite has a distinctive green color, for example.
Streak and Luster-Streak is the color of powder from a mineral and luster is how a mineral’s surface can reflect light.
Crystal Shape-Every mineral has a unique crystal shape. Crystals that form underground are large because magma cools slowly and small above ground because lava cools quickly.

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10. Chapter 2, Lesson 2, Minerals and Rocks Slide 9
-What are physical properties of minerals?
Cleavage and Fracture-Cleavage and fracture describe how a mineral breaks. If it breaks along smooth , flat surfaces, it has cleavage. If it breaks along a rough, irregular surface, it displays fracture.

11. Chapter 2, Lesson 2, Minerals and Rocks Slide 10
Density-Density is the amount of matter an object has per unit of volume. If you pick up a same sized piece of galena and quartz, you will find the galena to be heavier because it is denser than quartz.
*Some minerals have properties that make them easy to identify:
Magnetite can attract a magnet
In calcite, you can see two images of an object if you look through its crystals.
Graphite can be used to mark on paper..
-What are properties of minerals? Continued
*What are some other properties of minerals?

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-What are some uses for minerals?
-Some minerals are important because they contain materials that have many uses or because they have special properties or they are rare:
Metallic Ores-Ores are rich deposits of valuable minerals. The metals you use everyday come from these ores:
1. Galena is an ore that is used to make lead
2. Iron used to make steel comes from hematite and magnetite.

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-What are some uses for minerals? *
*What are rocks?
-Gemstones-Minerals that are collected for their beauty are called gems. They have intense colors, a glassy luster, and are a 7 or more on the Mohs scale. Diamonds, rubies, sapphires, and emeralds are among the most valuable gemstones.
*A rock is a natural, solid mixture of particles. These particles are made mainly of individual crytals , broken bits of minerals, or rock fragments. Most of the Earth is made of rocks.

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Iron
ore
Gems

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Diamond
Mining

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*What are Rocks? Continued
*There are three major types of rocks:
Igneous Rocks-Igneous rocks are formed from molten, or liquid rock material called magma. As the temperature in magma drops, tiny crystals of minerals begin to form becoming the grains of an igneous rock. Magma located above Earth’s surface is called lava. Since lava cools much more quickly than magma, the crystals in a lava, igneous rock are much smaller.

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Which igneous rock is made from magma?
magma

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*What are rocks? Continued
2. Metamorphic Rocks-They are rocks that form when solid rocks are squeezed, heated, or exposed to fluids, changing them into new rocks.
In order to be considered metamorphic rocks, they must stay solid as they change.
If the conditions are correct to melt them, new igneous rocks will form instead of metamorphic rocks.
The original rock that is changed is called the parent rock.

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Metamorphic
Rock

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-What are Rocks?
Continued
3. Sedimentary Rocks-Sediment is rock that is broken down into smaller pieces or that is dissolved in water.
Forces that cause erosion, such as water, wind, ice, and gravity move sediment to new locations.
Sediment is changed into sedimentary rock as grains are compressed by the weight of the material above them
The sediment grains also are cemented together by dissolved mineral material that crystallizes between grains.

22. Chapter 2, Lesson 2, Minerals and Rocks Slide 20
Sedimentary
Rock

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-What is the Rock Cycle?
-The rock cycle is the series of processes that change one rock into another.
-It happens so slowly that you usually do not notice it.
-It varies, but generally it can take many thousands to many millions of years for rock to transform.
-There are many different pathways through the rock cycle.

24. Chapter 2, lesson 3, Minerals and Rocks Slide 22
The Rock Cycle

25. Chapter 2, Lesson 2, Rocks and Minerals Slide 23
The Rock Cycle

26. Chapter 2, Lesson 2, Rocks and Minerals Slide 24
*Summary
*The Solid part of the Earth is made of minerals and rocks.
*Rocks fall into three categories:
Igneous-melted rock
Metamorphic-changed rock due to high pressure
Sedimentary-bits and pieces of rock that are pressed and cemented together
*As rocks form or change they go through a repeating cycle called the rock cycle.

27. Questions????? 1. What do human beings use minerals for?
2. In order to be classified as a mineral, what is one property it must have?
3. What is the hardest mineral on Mohs Hardness Scale?
4. What is one physical property of minerals?
5. What types of ores are used for their beauty?
6. What types of rocks are ones that have been heated and squeezed into new ones?