9.33 Types of Minerals

What are minerals? How do we use them? In this lesson, you will learn the answers to these questions as well as the different types of minerals and how scientists use physical properties to identify them.

What is a Mineral?

Minerals are everywhere, and we use them every day. They are found in the rocks we skip across a lake, the nails and bricks we use to build our houses, the cans our food and drinks come in, and the iron and steel that we use to make our cars. That is just a few examples of how we use minerals every day in our lives.

A mineral is a solid piece of matter that can be found in nature and has specific physical properties that can be used to identify it. Just like the examples above, there are thousands of different minerals in the world that are used to make thousands of different products that are part of our lives.

Minerals are often found in rocks and caves.

1. Main points:

Minerals are found in everyday objects like rocks, nails, bricks, cans, and in the making of cars. They are natural, solid materials with unique physical properties, and there are thousands of types used in various products.

2. Questions:

• Content Analysis: What are some everyday items that contain minerals?
• Contextual Analysis: In what contexts are minerals mentioned in the text?
• Thematic Analysis: What are the key characteristics of a mineral according to the text?

3. Further Discussion:

• If you could create a new product using a mineral, what would it be and why?

4. Answers:

• Content Analysis: "They are found in the rocks we skip across a lake, the nails and bricks we use to build our houses, the cans our food and drinks come in, and the iron and steel that we use to make our cars."
• Contextual Analysis: Minerals are mentioned in the context of being part of everyday life, such as in building materials and vehicles.
• Thematic Analysis: Minerals are described as "a solid piece of matter that can be found in nature and has specific physical properties."

Remember, when you answer these questions, think about how minerals are all around us in things we use every day. Can you imagine a world without them? What would it be like?

Properties of a Mineral

There are many physical features that scientists use to identify, or name, the different minerals. Here are some of the most common physical properties:

• Color – Scientists can use the color of the mineral to help tell what type it is.
• Luster – Luster is a fancy word scientists use to describe how the mineral reflects light. They observe the mineral to see if it is dull or shiny when the light reflects on it.
• Streak – The streak is the color the mineral makes when rubbed across something else. Surprisingly, sometimes the streak is different from the mineral’s color.
• Hardness – When scientists look at the hardness of a mineral, they look for items that can scratch the mineral, such as a penny or a nail. Scientists use a special test called the Mohs Hardness Scale to identify the mineral’s hardness.
• Specific Gravity – Scientists also use the density to help them identify the mineral. The specific gravity is a ratio between the density of the mineral and the density of a different material–usually water. In other words, it is a measure of how the atoms that make up the mineral are bunched together.
• Fracture/ Cleavage – These words describe how the mineral breaks into pieces. Scientists ask the question: ‘Does it break into a smooth surface or a rough surface?’

Scientists observe minerals and categorize them based on the physical properties.

1. Main points:

Scientists use physical features like color, luster, streak, hardness, specific gravity, and fracture/cleavage to identify and name minerals, each providing unique insights into the mineral’s properties.

2. Questions:

• Content Analysis: What are the different physical properties used by scientists to identify minerals?
• Linguistic Analysis: How does the text describe the property of ‘luster’ in minerals?
• Ideological Analysis: What does the use of the Mohs Hardness Scale indicate about the scientific approach to studying minerals?

3. Further Discussion:

• If you were a scientist, which physical property would you find most interesting to study in minerals and why?

4. Answers:

• Content Analysis: The physical properties include "Color, Luster, Streak, Hardness, Specific Gravity, and Fracture/Cleavage."
• Linguistic Analysis: Luster is described as "how the mineral reflects light" and is observed to be either "dull or shiny."
• Ideological Analysis: The use of the Mohs Hardness Scale shows that scientists rely on standardized tests and scales for accurate and consistent identification of minerals.

Think about how these properties make each mineral unique. If you had to describe a mineral you found, which of these properties would you use first? Why do you think that would be the best way to start?

Different Types of Minerals

Scientists usually begin by separating minerals into two groups: metallic and non-metallic. Metallic minerals have metal in them. This gives them a shiny luster. Non-metallic minerals do not contain metal. This gives them a dull luster.

Sometimes many minerals grow together. This rock has multiple minerals–some that have a dull luster and some that have a shiny luster.

Metallic minerals are further broken down into two more groups: ferrous and non-ferrous. Ferrous minerals contain iron. Some examples are iron ore, manganese, and chromite. We would use these types of minerals for things like steel to make buildings or tools. They could also be used for cast iron to make a frying pan your parents cook with.

Non-ferrous minerals do not contain iron. Examples of non-ferrous minerals are gold, silver, copper, and nickel. Do you have a necklace that you really love? It is probably made from a non-ferrous mineral like gold or silver. Also, the electrical wires in your house are probably made from copper.

See? These minerals from nature are used every day in our lives!

1. Main points:

Scientists categorize minerals as metallic or non-metallic based on metal content. Metallic minerals are further classified as ferrous (containing iron) or non-ferrous. These minerals are used in everyday items like buildings, tools, jewelry, and electrical wires.

2. Questions:

• Content Analysis: What are the two main categories of minerals and what distinguishes them?
• Contextual Analysis: How are ferrous and non-ferrous minerals used in our daily lives?
• Socio-cultural Analysis: Why do you think non-ferrous minerals like gold and silver are commonly used in jewelry?

3. Further Discussion:

• If you could find a new mineral, what properties would you want it to have and how would you use it?

4. Answers:

• Content Analysis: "Scientists usually begin by separating minerals into two groups: metallic and non-metallic."
• Contextual Analysis: "Ferrous minerals…used for things like steel to make buildings or tools" and "Non-ferrous minerals…like gold or silver…electrical wires in your house are probably made from copper."
• Socio-cultural Analysis: The text does not directly answer this, but it implies that non-ferrous minerals like gold and silver are valued for their appearance and rarity, making them desirable for jewelry.

Imagine being a scientist and discovering a new mineral. What would you name it, and what cool things could it do?

Lesson Summary

Minerals are natural solid materials that are identified by their physical properties. Scientists use the physical properties of color, hardness, luster, fracture/cleavage, streak, and specific gravity (this deals with density, or how the atoms that make up the mineral are bunched together,) to identify and name the minerals.

Scientists also put minerals in categories based on what they are made of. Metallic minerals contain metal, while non-metallic minerals do not. Ferrous metallic minerals contain iron, while non-ferrous minerals do not.