Minerals

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)