1. Properties of Minerals

2. Target #12- I can state how minerals are classified
Minerals are classified by their properties
Some are easy to study, other require equipment
Determined by the chemical composition and crystalline structure
Properties
Color
Streak
Luster
Cleavage & Fracture
Hardness
Crystal Shape
Density

3. Target #13- I can explain why color is an unreliable clue to the identify of a mineral
Easy to observe with the naked eye
Example
Quartz
Pure: colorless
Amethyst: purple (due to the presence of iron and manganese)
Sapphire
Medium to dark blue in color
Caused by the presence of iron and titanium
Not generally reliable for identifying a particular mineral
Weathered surfaces may hid the color of minerals

4. Target #14- I can state how you would determine the streak of an unidentified mineral
The color of the mineral in a powdered form
Easiest way to observe is to rub the mineral against a piece of unglazed tile
Different minerals produce different streaks
Example
Pyrite gold in color, streaks black
Minerals harder than the tile will not streak

5. Target #15- I can describe two types of luster
Light that is reflected on a mineral’s surface
Either metallic, can reflect light, or non-metallic
Non-metallic luster is broken down further
Waxy luster
Look like candle wax
Glassy luster
Look like glass
Pearly luster
Look like pearls
Dull luster
Lacks any shiny appearance

6. Target #16- I can contrast cleavage and fracture
Cleavage & Fracture
Cleavage: the tendency of a mineral to split along specific planes of weakness to form smooth flat surfaces
Weaknesses tend to run parallel
Example
Mica split into sheets
Fracture: minerals can break unevenly into pieces that have curved or irregular surfaces
Described according to their appearance

7. Target #17- I can summarize how you would determine the hardness of an unidentified mineral sample
The measure of the ability of a mineral to resist scratching
Can be determined by using the Mohs hardness scale
Scratch an unknown mineral to those found on the hardness scale
To test for hardness, you must determine the hardest mineral on the scale that the unknown mineral can scratch
If you scratch the unknown with the known, and vice versa, and they do not mark each other, then they are the same hardness

8. Target #18- I can state how environmental conditions impact mineral formation
Crystal Shape
Forms into one of six basic shapes
Can become more complex as a result of environmental conditions during crystal growth
Example
Temperature
Pressure

9. Target #19- I can explain the apparent weight differences observed between minerals of the same size
Density
The ratio of the mass of a substance (how much “stuff” is in it) to the volume of the substance (how much space there is)
The more tightly packed the atoms, the more dense a substance is
Explains the apparent differences in weight between minerals of the same size