Dr. Passow Name:

Science 8

MINERAL IDENTIFICATION

General directions:

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Part 1. GENERAL PROPERTIES OF MINERALS

1. Name four characteristics of all minerals.

 2. Tell three ways in which minerals are different from rocks.

 3. Approximately how many minerals have been identified?

 4. Name eight minerals commonly found in rocks.

Part 2. IDENTIFYING MINERALS

Note: You may work through these in any order—if another group is using the samples for the characteristic you want to study, go to another and come back to that one.

1. HARDNESS

A. What is meant by "mineral hardness"?

B. On the Mohs’ scale, what is the

C. Using the testing sets provided, find the hardness of

2. DENSITY

A. What is meant by "mineral density"?

B. What is another term that is often used to indicate the mineral’s density?:

C. Using a balance scale and graduated cylinder, students found the densities of three samples. Use the information provided to complete the table below.

3. COLOR

A. Explain why some minerals have only one color that immediately helps in identifying them, and other minerals may come in a wide variety of colors.  

B. What is the characteristic color of:

sulfur:

fluorite:

azurite:

malachite:

pyrite:

hematite:

4. LUSTER

A. What is meant by "mineral luster"?

 B. Name three minerals that show a "metallic" luster, and three with a "nonmetallic luster."

5. CRYSTAL FORM/SHAPE

A. What does "crystal form" or "crystal shape" mean?

 B. What creates the crystal form of a mineral?

C. What is the crystal shape of these minerals:

Quartz:

Halite (rock salt):

Galena:

Calcite:

Garnet:

Pyrite:

6. CLEAVAGE and FRACTURE

A. What is meant by "mineral cleavage?"

B. How is "fracture" different from "cleavage" in minerals?

C. What mineral is easily identified because it cleaves into thin sheets? Name its two common varieties.

D. What happens when a piece of calcite is struck by a hammer?

E. Quartz does not break along flat cleavage surface, but does have a characteristic fracture pattern—what

shape is the surface of broken quartz?

7. STREAK

A. What is meant by the "streak" of a mineral?

 B. Use the streak plate or your resources to find the typical streaks of these minerals:

Hematite:

Galena:

8. SPECIAL IDENTIFICATION TESTS

A few minerals can be easily identified by special tests. Use the sample available to learn about these.

A. "ACID TEST"

Watch as your teacher pours a little dilute hydrochloric acid (HCl) on calcite, and describe what happens.

Repeat this with a sample of quartz.

B. FLUORESCENCE (learn how to spell this correctly!)

Some minerals glow or "fluoresce" when they absorb invisible "ultraviolet" energy. You may be familiar with this from an amusement park or other place where you have an invisible stamp on your hand that shows up when placed under a "black light."

Examine the samples provided. When they fluoresce, white calcite turns: and orange willemite turns:

C. TASTE

YOU SHOULD NOT TASTE MOST MINERALS, because they may be poisonous (and nasty-tasting!) One minerals, however, is easily identified by its taste. This is halite, or rock salt. Touch the tip of a finger to your tongue, then touch the sample, and then back to your tongue. Is it salty?

Besides "salty," what are the other three types of "taste buds" on your tongue?

Part 3. OTHER QUESTIONS ABOUT MINERALS

1. What are two useful properties that make a mineral useful as a gemstone?

2. Look around the room and name at least five products that come from minerals. If possible, name the minerals they come from.

Complete the chart below: