let’s talk minerals. warm up!! how are rocks and minerals related?
TRANSCRIPT
Let’s Talk Minerals
WARM UP!!
How are rocks and minerals related?
What is a mineral?
It is a naturally occurring, inorganic substance which has a definite chemical composition.
It must exist as a solid on Earth under normal conditions!
The atoms that make up the substance must be arranged in an orderly structure, so it has a definite crystal structure.
What is the opposite of this? Organic, man-made, random composition, and unorganized crystal structure
What causes minerals to have different physical properties?
the internal arrangement of their atoms
Minerals maybe made up of the same elements and have the same chemical formulas, but due to differences in the environments in which they formed, exhibit different physical properties!
Can you give an example of two minerals which have the same chemical composition
but different physical properties?
Graphite and diamonds are both made of carbon, and are sometimes found together. Diamonds are formed under extreme heat and pressure, graphite forms when the heat and pressure are not as intense.
Any questions so far?Any questions so far?
The Main Physical Properties Used to Identify Minerals
Color
a poor indicator
minerals can be multiple colors
many minerals are the same color
The Main Physical Properties Used to Identify Minerals
Streak
The streak of a mineral is the color it displays in finely
powdered form. The streak maybe completely different from the color of the hand specimen.
One of the simplest ways of determining the streak of a mineral is to rub a specimen across a piece of unglazed
porcelain known as a streak plate.
The Main Physical Properties Used to Identify Minerals
Streak
the powder form of a mineral
more reliable than color
The Main Physical Properties Used to Identify Minerals
Luster
how light reflects off a mineral
metallic non-metallic
looks like a metal
looks earthy, waxy, greasy or brilliant
The Main Physical Properties Used to Identify Minerals
Luster
how light reflects off a mineral
metallic non-metallic
Cleavage
The Main Physical Properties Used to Identify Minerals
the mineral breaks in a predictable patternbecause of its arrangement of atoms
Fracture
The Main Physical Properties Used to Identify Minerals
the mineral breaks randomly
Hardness
The Main Physical Properties Used to Identify Minerals
Is resistance to being scratched
It is NOT the same as breaking!
For example: You can break glass easily with steel.However, steel will not scratch glass.
Hardness
The Main Physical Properties Used to Identify Minerals
MOH’S SCALE OF HARDNESS
Hardness
Mineral Hardness
Mineral
1 (softest) 6
2 7
3 8
4 9
5 10 (hardest)
TALC
GYPSUMCALCITE
FLUORITE
APATITE
ORTHOCLASE
QUARTZTOPAZ
CORUNDUMDIAMOND
Minerals have a definite chemical composition.
There are two elements that, by mass,
make up most of the Earth’s crust
Minerals have a definite chemical composition.
These two elements combine to form compounds called
silicates (SiO4)
Minerals have a definite chemical composition.
They combine in a specific structure called a:
silicon-oxygen tetrahedra
All silicates have some form of SiO4 their chemical formula.
Ticket Out The DoorAnswer the Following Questions:
1. What are the five things required for something to be a mineral?
2. List 5 things that contain minerals.3. Is liquid mercury a mineral? Why or why
not?4. What two substances have the same
chemical make up but look completely different?
Tomorrow we will:Discuss mineral
identificationDiscuss the use of
minerals and rocks around us
Look at rock and mineral samples