Minerals
Feb 23, 2016
Minerals
I. Minerals• A naturally occurring, inorganic,
crystalline solid having a definite chemical composition.
A. Characteristics1. Where can we find information to help
us ID minerals? ESRT p.16
Back of the ESRT
2. Color:
a) Many different minerals have the same color.
b) The same mineral may have many different colors.
A POOR way to identify a mineral.
Quartz
Calcite
HaliteDifferent
ColorQuartz
3) Streak: The color of the powder of a mineral when it is crushed.
4) Hardness:
a. The ‘streak’ of a mineral is not a hardness test, but minerals with a hardness of more than 7 will scratch the plate.
b. To find the hardness of a mineral you use objects of a known hardness to see if they will scratch the mineral.
The resistance of a mineralto being scratched.
Hardness of Common Materials:
Fingernail = 2.5 Penny = 3.5 Iron Nail = 4.5Glass Plate = 5.5 Streak Plate = 7.0
5) Luster: The shine from a mineral’s Surface or the way a mineral looks in reflected light.
6) Cleavage:The way a mineral will breakalong areas of weakness andform smooth parallel sides.
7) Fracture:The uneven breaking of amineral because it doesn’t have specific weak areas.
Which shows Cleavage and which shows Fracture?
CleavageFracture
Questions:1. What is the hardness of Olivine?– Olivine’s hardness is 6.5
2. How does Pyroxene break?– Cleaves in 2 directions at 90 degrees.
3. What is the chemical symbol for Sulfur?– Sulfur’s chemical symbol is “S”.
4. What is the Luster of Galena?– Galena has a Metallic Luster
5. What is Talc used for?– Talc is used in Talcum (baby) power.
6. Which mineral has a hardness of 2.5, is flexible in thin sheets, and is black in color?– Biotite Mica
B. Chemical Composition• _______ and _______ are the two most
abundant elements by mass in the Earth’s crust.
Silicon Oxygen
C. Mineral StructureInternally, minerals are made up of atoms arranged in a specific pattern. This pattern will determine ALL of
the physical and chemical properties of the mineral.
1) Over 90% of Earth’s minerals are ________.Silicates
D. Misc. Mineral Information1. A “Carbonate” mineral reacts with
______________ and ‘bubbles’.Hydrochloric Acid
2. Diamond and Graphite are both made of the same material, ______.
a) Diamonds are connected by a _______ network.
b) Graphite is set up in ______ and flakes off easily.i. Diamond has a hardness of _____, while
Graphite’s hardness is ______.
CarbonLattice
Layers
101 -2
3)We identify minerals based on Two [2] Properties, they are: _______ and ________.
PhysicalChemical
Questions1. What is the difference between a
Cleavage and Fracture? – Cleavage is the way a mineral breaks along
a smooth, parallel sides, while Fracture is an uneven breaking.
2. What are the 2 ways that we classify a minerals Luster? – Metallic and Non-Metallic
3. How would you tell the difference between Calcite and Halite? – Calcite will react with HCl & Halite has cubic
cleavage.
4. If a mineral can scratch a fingernail, penny, but NOT scratch an iron nail, its hardness must be – About 4.
5. What type of minerals will react or bubble when touched with acid and give an example of the specific mineral?– A carbonate mineral – Calcite (CaCO3)