How can we identify a mineral or a rock?

GPS S3E1b. Recognize the physical attributes of rocks and minerals using observation, measurement, and simple tests.

…by its hardness

Talc is the softest mineral.

Diamond is the hardest mineral.

Let’s do the hardness or scratch test!

• You will need: your fingernail, a penny, a concrete nail, different kinds of minerals, and the Mohs Scale of Hardness chart below.

Bring out your rock and test its hardness by doing the scratch test!

…BY ITS COLOR

This is the mineral talc.

This rock called granite has 3 colors which means it has 3 kinds of minerals.

But wait!!!

• We cannot identify all rocks and minerals just by looking at their color/s.

• Why? Can you tell which is gold and which is pyrite (fools gold)?

So we need the other properties of minerals to help us identify them.

• Streak is another property. It is the color of the fine powder produced when a mineral is rubbed against a hard surface.

Do your own streak test using your pet rock.

…another property of mineral is luster.

• Luster describes how light bounces off (reflects) a mineral.

• Which is metallic and shiny and which is dull?

The texture or the “feel” of a mineral depends on the size of its particles.

This mineral has very tiny particles. It has a smooth texture.

This mineral has big particles. It has a rough texture.

The way to identify rocks and minerals is learning about their properties:

• Color• Streak• Hardness• Luster• Texture

Let’s Review!

• Read pp. 124 and 125 of your book. Use the pictures to help you understand what you read.

Now it’s your turn to identify your rock!

• Adopt a pet rock. • Fill out the chart. Make your pet rock “look good” by following the rubric.

Rubric for your pet rock4 Points (100%) 3 Points (75%) 0

Student’s information is correct. He/she wrote in complete sentences.

Student’s information is correct. He/she did not write in complete sentences.

Student’s answer is wrong.