Sci-ber Text - 8th Grade

Rocks & Minerals - What's My Story?

On the previous Sci-ber text page, you learned that rocks are made of minerals. Now you get to learn more about the different minerals which are found on Earth. Look closely at each image and the description next to it. Notice that you can describe each mineral based on observable properties.

Pyrite is a very important iron ore mineral. Many early prospectors mistook it for gold, hence the nickname, Fools' Gold.

Galena is a valuable ore for lead, since lead doesn't occur naturally alone. Because galena is made mostly of lead, it is very heavy for its size.

Magnetite is another iron ore. Iron molecules line up north and south while in the liquid state making a natural magnet.

Sulfur occurs as an element. Man uses it in a variety of ways and it has a very distinct rotten egg smell.

Calcite is found in nature in caves, seashells, eggshells and bones. Acid will make it bubble.

Quartz is found in a lot of the rocks in Earth's crust. People also like it to make jewelry.

Muscovite comes in light-colored paper-like sheets. Early settlers used large sheets as windows in their homes.

Biotite is a dark version of muscovite.

Hematite is an iron ore mineral. It has a distinctive red streak (even though the mineral sometimes is black!) You have probably seen it as metallic black jewelry.

Talc is a familiar mineral, best know for being talcum powder (baby powder.)

Hornblende is a very dark, fibrous mineral found in many rocks.

Feldspar is the largest rock forming mineral. It is found in a variety of colors.

Graphite is made of the same element as diamonds, but it is really soft. It is used as a dry lubricant and also as the "lead" in your pencil.

Now that you have learned about the different minerals, it is time to try to identify them in a lab situation. Good luck!

In this activity you will be studying minerals and how to identify them. Remember that a mineral is a naturally formed substance. You can identify a mineral by its properties. Such as its color, hardness, luster, streak, and even by some unique properties such as smell. You will identify the minerals using a simple dichotomous key.

Materials:

Steel nail
Streak plate
A variety of minerals from the following list:
- Pyrite
- Galena
- Magnetite
- Sulfur
- Iceland spar
- Calcite
- Milky quartz
- Biotite
- Hematite
- Muscovite
- Talc
- Hornblende
- Graphite
- Feldspar (Plagioclase, or Orthoclase)

Procedure:

Do not break or harm the minerals in any way!
Use a different number for the identification of each mineral you test.
As you are given a mineral take a few seconds to look at its properties before you start.
Read the first question of the Get a Clue dichotomous key.
- Click on yes or no as it pertains to the mineral you are looking at.
- You will automatically be taken to the next screen.
- Keep doing this until the screen tells you what your mineral is.
- Write the name of the mineral next to the appropriate number and write any other information that will help you remember what the mineral is.
Continue identifying each mineral (remember to start at the first question of the Get a Clue dichotomous key.)

Safety concerns: This lab is about mineral identification, not about the aerodynamics of rocks or the practice of ancient surgical procedures using only a sharp object like a nail. Please remember that minerals get very lonely without their fellow minerals due to the fact that they are of a gregarious in nature. So please make sure that after the activity that all minerals are placed back with their loved ones. As with all science lab activities, the most important safety rule is to follow all teacher directions.

Obtain five new minerals (examples: halite, gypsum, limonite, bauxite, and fluorite.)

Add to the dichotomous key using these new minerals!

Analysis.

In what ways are minerals similar to one another?
What differences did you discover as you identified the minerals?
Which mineral was the easiest to identify?
Which mineral was the most difficult to identify?