Activity 3

Physical Properties of Minerals

Introduction

Minerals make up the rocks beneath your feet, the soil that supports plants, and the deep rock of Earth’s mantle. Any thorough study of Earth must include an understanding of minerals. But it is not sufficient to study minerals isolated from the rest of the planet. Rather we can learn more by observing the ways that minerals interact with other Earth systems.

Content

Mineral Identification

In this virtual investigation you will identify minerals by observing and testing their physical properties. After gathering data for an unknown mineral, you will refer to an identification chart to determine the mineral's identity.

Minerals are the building blocks of rocks. Mineralogists use the criteria to determine whether a material is classified as a mineral or not.

Characteristics of Minerals

1. naturally occurring- a product of Earth’s natural processes

2. inorganic- it must be product of Earth’s physical processes.

3. homogeneous solid- minerals should have definite volume and rigid shape

4. definite chemical composition—represented by a chemical formula

5. orderly crystalline structure- atoms of minerals are arranged in an orderly

and repeating pattern

Properties of Minerals

To identify minerals, mineralogists observe the following properties:

a. Color - mineral’s color may change depending on the surface.

b. Streak - color of mineral in powdered form.

c. Hardness - minerals resistance to scratching

Mohs Scale of Hardness (Diamond is the Hardest with a scale of 10)

10 - Diamond

9 - Corundum

8 - Topaz

7 - Quartz

6 - Orthoclase

5 - Apatite

4 - Fluorite

3 - Calcite

2 - Gypsum

1 - Talc

d. Cleavage - mineral’s resistance to being broken and fracture

e. Crystalline structure or habit

f. Diaphaneity/amount of transparency - ability to allow light to pass

through it. This is affected by chemical makeup of the mineral sample.

g. Luster - how light is reflected off a surface

h. Tenacity - describes the minerals reaction to stress.

Brittleness- a mineral turns into powder

Malleability a mineral can be flattened by pounding with a hammer.

Ductility- A mineral can be stretched into wire.

Flexible but inelastic-Minerals are bent but they remain in the new position.

Flexible and elastic- Minerals are bent, and they bring back to their original position.

Sectility- ability of minerals to be sliced by a knife.

Objective

In this virtual investigation you will identify minerals by observing and testing their physical properties.

Material

Rocks/mineral
Pen and paper
Coin
Books about Rocks or Internet

Procedure

1. Look for 3 minerals that can be found inside your house.

2. Label the minerals A, B, and C.

3. Observe the color and distinguishing features of the minerals.

4. Scratch the mineral with a coin and your fingernail and if it can be

scratched, write yes with the last two columns. Write no if it can't be scratched.

Observation Table for color, feature and hardness

Guide Questions

1. Based on your data above, what are the observable characteristics of minerals you gather?

2. Can you mention other physical properties of minerals aside from the things you mention?

Conclusion:

Presentation

Evaluation

*adopted from the Module of the division of Pasig pp.11

Reference

GEOLOGY LABORATORY: MINERAL PROPERTIES Last Revised August 27, 2012 https://www.saddleback.edu/faculty/jrepka/notes/GEOmineralLAB_1.pdf.

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