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.

3. Chapter 2, Lesson 2, Minerals and Rocks Slide 2
-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 Mohrs developed a hardness scale of 1 to 10 with the hardest mineral, diamond, being a 10 and the softest, talc, being a one.

7. Chapter 2, Lesson 2, Minerals and Rocks Slide 6
Mohs Scale of hardness

8. Chapter 2, Lesson 2, Minerals and Rocks Slide 7
-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 because magma cools slowly and small above ground because lava cools quickly.

9. Chapter 2, Lesson 2, Minerals and Rocks Slide 8

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 long 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 of minerals?

12. Questions????? 1. What do human beings use minerals for?
2. In order to be classified as mineral, what is one property it must have?
3. What is the hardest mineral on Mohs Hardness Scale?