Activity: Mineral Properties

Introduction

            More than 2,000 minerals are now known, and several more new ones are recognized each year. Although some can only be identified by complex chemical and physical testing, most can be named by simple tests based on their more obvious properties or characteristics.  In this activity, you will learn what these are. In the next activity, you will use these to identify some of the most common minerals.

Procedure

            Use your resources to find answers to the questions that follow, and then type in the answer. If possible, include an image to illustrate what you write.

 Web Sites to Start from

            http://www.mii.org (Mineral Information Institute)

            http://volcano.und.nodak.edu   (University of North Dakota’s Volcano World)

            http://www.usgs.gov  (U. S. geological Survey)

Chemical composition

1.       What are the two most abundant elements in Earth’s crust? What do we call minerals that contain these elements?

2.       Name six other minerals commonly found in the crust?

3.       Name the key elements/molecules found in

--carbonates

--oxides

--sulfides

--sulfates

      4. What are “native elements”?

Crystal Shape (form)

1.       What produces the shape of a mineral’s crystal?

2.       How many different basic crystal systems exist? Name them.

3.       Tell the typical crystal shape of

--quartz

--calcite

--pyrite

--garnet

4.       What aren’t minerals always found as crystals? That is, why are most “massive”?

Luster

1.       What does “luster” mean?

2.       Name some types of luster found in minerals.

3.       Name three minerals that show “metallic” luster.

4.       What kind of luster is found in

--quartz

--pyrite

--mica

--feldspar

Color

1.       What factors produce a mineral’s color?

2.       Why do some minerals occur commonly in several varieties of color?

3.       Name four color varieties found among quartzes?

4.       What creates some of the color variety found among the feldspars?

5.       Name three other minerals that can be quickly identified by their color.

Streak

1.       What is meant by a mineral’s “streak”?

2.       What aren’t color and streak always the same?

3.       What are the typical streaks of

--quartz

--feldspar

--calcite

--pyrite

--limonite

--hematite

Cleavage and fracture

1.       What is meant by mineral “cleavage”?

2.       How does “fracture” different from cleavage?

3.       What mineral is easily recognized by its cleavage into thin sheets? Name the two common varieties of this mineral.

4.       What is the typical fracture pattern found in quartz?

Hardness

1. What is meant by a mineral’s “hardness”?
2. List the minerals of the Mohs Scale, from 1 to 10.
3. What is the hardness of these common items often used by geologists to test mineral samples:

--fingernail

--penny

--penknife blade

--piece of glass

4. Explain why diamond can be the “hardest” known substance, yet so brittle it can crack if dropped.

Density

1. What determines the density of a mineral?
2. What is meant by “specific gravity”?
3. Name two minerals that have very high densities.
4. Explain how the high density of some minerals produces valuable “placer deposits,” and name two minerals that are sometimes mined in this way.

Special Properties

1. What is a characteristic often used to identify calcite and other carbonates?
2. What is a special property of halite?
3. What is a special property of lodestone (magnetite)?
4. What is a special property of willemite?

Using the E.S. Reference Tables: “Properties of Common Minerals”

1. List the order to use the properties listed in the table.
2. Which mineral is in many foods you eat?
3. Name some common uses of minerals with a hardness of less than 3?
4. What is a property that makes some minerals suitable for use in jewelry?

List the resources you used: