LESSON 3_ ROCK FORMING MATERIALS Flashcards
is inorganic substance that are made up of one or a number of chemical elements with a definite chemical composition. It is also not man made
Minerals
Physical Properties of Minerals
- Color
- Hardness
- Luster
- Streak
- Specific Gravity
- Fracture
- Cleavage
- Crystal form
Refers to how light is reflected from the surface of a mineral.
Luster
Luster: Shiny, Sparkling
Metallic
Luster: Dull, Greasy, Vitreous, Glassy
Non- Metallic
The ability of mineral to resist scratching.
Hardness
A German mineralogist who developed a hardness scale over 100 years ago.
Friedrich Mohs
Measures the scratch resistance of various minerals from a scale of 1 to 10, based on the ability of a harder material/mineral to scratch a softer one.
Mohs Scale
Mohs Relative Hardness Scale: It flakes easily when scratched by a nail
1
Example of Mohs Relative Hardness Scale 1
Talc/ Talcum powder
Softest known material
Mohs Relative Hardness Scale: A fingernail can easily scratch it
2
Example of Mohs Relative Hardness Scale 2
Gypsum
Ingredient of Plaster
Mohs Relative Hardness Scale: A fingernail cannot scratch it, but a Copper penny can
3
Example of Mohs Relative Hardness Scale 3
Calcite
FOund in Cement
Mohs Relative Hardness: A steel nail can easily stratch it
4
Example of Mohs Relative Hardness Scale 4
Fluorite
Found in toothpastes
Mohs Relative Hardness Scale: A steel nail can scratch it
5
Example of Mohs Relative Hardness Scale 5
Apatite
Mineral found in our bones
Mohs Relative Hardness: Cannot be scratched by a steel nail but it can scratch glass
6
Example of Mohs Relative Hardness Scale 6
Feldspar
Ingredient in Glass
Mohs Relative Hardness Scale: Can scratch steel and glass easily
7
Example of Mohs Relative Hardness Scale 7
Quartz
Used in Glass
Relative Hardness Scale: Can scratch quartz
8
Example of Mohs Relative Hardness Scale 8
Topaz
Gemstone
Mohs Relative Hardness Scale: Can scratch Topaz
9
Example of Mohs Relative Hardness Scale 9
Corundum
Rubies and Sapphires
Mohs Relative Hardness Scale: Can scratch all the other minerals
10
Example of Mohs Relative Hardness Scale 10
Diamond
Hardest known mineral
Refers to the characteristic shape of a mineral unit which are visible (either an individual crystal or a group of crystal).
Crystal form habit
- Visual appearance of the mineral
- Least useful property in identifying minerals (Minerals could have similar color and some could be altered by impurities)
Color
- Is the mineral’s color in powdered form. It can be useful for identifying metallic and Earthy minerals.
- Non-metallic minerals usually give a white streak because are very light- colored.
- Other minerals may have distinctive streaks. Ex: Hematite, always gives a reddish-brown streak no matter what type of luster
Streak
- It is the ability of a mineral to break along preferred planes.
- The number of ________ planes in a mineral may also aid its identification.
- Typically occurs in either one, two, three, four or six dimensions.
- The tendency of a Mineral to break evenly along its weakest
plane. (Smoothly/ evenly)
Cleavage
The tendency of a mineral to break unevenly/ irregularly
Fracture
- Is the “heaviness” of a mineral.
- The ratio of the density of the mineral to the density of water (1g/cm cubed)
Density= Mass/ Volume
Specific Gravity
Special Property
Produces a chemical reaction when a drop of weak acid is placed on fizzes (produces bubbles)
Example: Calcite
Fluoresence
How to identify the volume of an irregularly shaped mineral?
Water displacement
How much it elevates
Special Property
When a mineral is magnetic
Example: Magnetite
Magnetism
Special Property
Having distinct taste
Example: Halite (Salty)
Taste
Special Property
Having a distinctive smell
Example: Sulfur
Odor
Special Property
