1. Minerals

2. Vocabulary
Mineral - a crystalline/inorganic substance made of one pure substance
Color - the outer visual appearance of the mineral
Streak - color left by a mineral that is scraped on a surface.
Luster - a mineral’s ability to reflect light
Hardness - how easily a mineral can be scratched
Mohs Scale - a scale used to classify minerals according to their hardness
Density - a measure of the mineral’s mass compared to its volume (d=m/v)

3. What is a Mineral? Minerals are the “building blocks” of rocks
Rocks are made up of different combinations of minerals
Different minerals are formed from different combinations of elements
4 Questions to Ask:
Is it a nonliving material?
Is it a solid?
Does it have a crystalline structure?
Is it formed in nature?
You must be able to answer “yes” to ALL 4 QUESTIONS in order for something to be a mineral.

4. 2 Groups of Minerals Silicate Minerals Made up of silicon and oxygen
The specific type of mineral is determined by the other “ingredients”
Make up 90% of the Earth’s crust
Nonsilicate minerals
Is NOT made up of silicon and oxygen
It could have one or the other, but not necessary

5. Properties of Minerals
Color
Luster
Streak
Cleavage/Fracture
Hardness
Density
Other Special Properties

6. Color
The same mineral can come in a variety of colors depending on impurities and exposure.
Exposure to air, water, and extreme temperatures can alter the color of a mineral
Color is not a reliable way to identify minerals because the color can vary

7. 5. Hardness A mineral’s resistance to being scratched
Mohs Hardness Scale includes “references” to help determine a mineral’s hardness
Example: Steel nail = 6.5
A steel nail does not leave a scratch on the mineral
Harder than a steel nail, > 6.5
A steel nail does leave a scratch on the mineral
Softer than a steel nail, <6.5

8. 3. Streak
The color left behind when you rub the mineral on a streak plate
A small amount of powdered mineral left behind
The streak color is not necessarily the same color as the mineral!
Streak color is more reliable than mineral color when identifying minerals because the streak color is not affected by exposure to air, water, etc.

9. 2. Luster Luster is the way a surface reflects light Metallic (shiny)
Nonmetallic (dull)
Minerals can appear nonmetallic if they are dirty, so it’s important to make sure the mineral you are identifying is clean!

10. 4. Cleavage/Fracture
Cleavage - when a mineral breaks apart with smooth, flat edges
Fracture - when a mineral breaks apart with jagged, uneven edges
To test a mineral’s cleavage or fracture pattern, you can use a hammer to break off a small section of the mineral.
Using a hand lens or microscope is sometimes necessary to view the cleavage patterns

11. 6. Density Golf ball (high density) vs. tennis ball (low density)
Measures how much mass is in a given amount of space
Mass divided by volume
We can measure a mineral’s mass using a triple beam balance
We can measure a mineral’s volume using a graduated cylinder
Mass (grams, g)
Volume (milliliters, mL
or cubic centimeters, cm3)

12. 7. Other Special Properties
Magnetism
Reactivity
Taste
Fluorescence
Radioactivity
Optics

13. What is a Mineral?
Minerals are naturally occurring solid substances that are made up of only one substance.
Minerals are “inorganic” (nonliving)/crystalline” substances
Minerals are classified by characteristics such as color, hardness, streak, and luster
Color-
The color of a mineral can set it apart from other minerals. Some minerals are the same color and must be investigated further to determine their composition
Hardness -
When would you use the Mohs Scale?
-When you’re trying to identify a mineral based on its hardness

14. What is a Mineral? Streak -
Streak is the colored powder left behind when a mineral is scraped on a surface.
Does the “streak” always match the mineral’s color
Luster
Luster is a measure of how much light the mineral reflects… like a mirror
Luster can be either metallic, non-metallic, earthy, or glassy