Download I. Minerals

Aim: What is a Mineral?
Do Now:
Minerals are used in our everyday lives.
In your notebook, try to think about and
list the ways minerals are used by you
and me every day.
I. Minerals:
are classified as…
a. Naturally occurring
b. Solid substance
c. Orderly crystalline structure (specific shape)
d. Definite chemical composition (the
elements that it is made of)
e. Inorganic (not living)
II. How do Minerals Form?
1. Crystallization (to form a crystal)
- hot material (magma/lava) cools, forcing
elements within to combine and harden forming
minerals.
Pyrite
Graphite
Galena
2. Precipitates/Evaporites
- solid substances dissolved in water are left behind
to form crystals when the water evaporates.
Like Rock Candy or the ring around your bathtub
Salt Flat - Halite
Limestone Cave
3. Hydrothermal Solutions
- Very hot solutions cause chemical reactions with
existing minerals to form new minerals
(recrystallization).
Pyrite
Quartz
III. Silicon-Oxygen Tetrahedron
- Most abundant atomic
structure in Earth’s crust.
(there is a lot of it)
- Found in Quartz (sand) and
makes quartz very strong
(resistant to breaking)
Review Questions:
1) What are the five characteristics of all minerals?
Minerals are naturally occurring, inorganic,
solids, with definite crystal shape and definite
composition.
2) Where does the material come from to undergo crystallization?
The material comes from the inside of the Earth
or a volcanic eruption. The material has to be
extremely hot!
3) Describe the process of the formation of a precipitate.
Material needs to be dissolved in water. Later, the
water is evaporated leaving the mineral behind.
Solid materials can not be evaporated like water.
Aim: What Properties Help Identify
Minerals?
Do Now: How can a scientist tell
the difference between different
minerals? List some of the
properties you would look for to
classify a mineral.
Use your ESRT page 16 to help
determine useful properties.
I. Properties of Minerals
Depend on:
1) The chemical composition of the mineral.
(the elements it is made up of)
2) How the mineral’s atoms are arranged
internally (structure).
Non-Metallic
We will take notes on each section of this table
Take out Page 16 of your ESRT
1. Color (least significant property)
- cause by impurities that can affect the color of
any mineral.
Why is color the least significant property?
Quartz
Calcite
Talc
Halite
2. Streak
- the color of a mineral in its powdered
form.
- found by rubbing a mineral across a streak
plate (a piece of porcelain.)
- A minerals streak is
identified as either;
Color – any color
Colorless – clear, white or no streak
3. Luster
- describes how light is reflected from the
surface of a mineral.
Pyrite
Galena
Metallic
Looks like metal
Sulfur
vs.
Feldspar
Non-Metallic
Doesn’t look like
metal
4. Crystal Form – Shape of the mineral
Garnet
Calcite
Quartz
5. Hardness
- the resistance of a mineral to being
scratched compared to known objects
on Mohs scale of hardness. (arranged
from 10 (hardest) to 1 (softest))
- determined using a glass plate.
1. If it scratches the glass, then the mineral is
harder
2. If it doesn’t scratch the glass, then the
mineral is softer.
6. Breakage
- the tendency of a mineral to break apart into
pieces.
A) Cleavage
- Minerals appear to have right angles, flat
surfaces, boxed appearance.
Mica
Calcite
b) Fracture
- the uneven breakage of a mineral.
Sulfur
Quartz
7. Distinctive Properties of Minerals
- Some minerals can be recognized by other
distinctive properties (magnetism, smell)
- Effervescence (bubbling)
using Hydrochloric Acid indicates the
presence of calcium (Calcite.)