Transcript Rocks & Minerals

Rocks & Minerals
THE DIFFERENCE BETWEEN
ROCKS & MINERALS
•It is not easy to tell the difference between
rocks & minerals because there are so many
kinds of them.
There are 3000 known minerals on Earth!
There are 3 main rock types but hundreds
of sub-categories
It takes years of study to be able to
accurately identify a mystery rock and even
then geologists want to know where the
specimen came from.
First the basics:
1. All rocks are made of minerals.
2. A rock is made up of 2 or more minerals.
3. You need minerals to make rocks, but you
don't need rocks to make minerals.
Think of a chocolate chip cookie as a rock.
The cookie is made of
flour, butter, sugar &
chocolate
The cookie is like a rock
and the flour, butter,
sugar & chocolate are
like minerals.
In your notes finish this
sentence:
A chocolate chip cookie is
like a rock . . .
Leave
MY
cookies
alone!
Rocks are divided into: 3 Types
They are classified by:
How they were formed
The three types include:
1. Igneous
2. Sedimentary
3. Metamorphic
Rock Words: There are many common names for rocks and
the usually give you an idea of how big the rock is. Here are
a few:
mountain
- huge, giant hunk of rock that is still attached to the
earth's crust, doesn't move, tall
boulder
- large, taller than a person
rock
- large, you could get your arms around it or a bit smaller
but it is usually jagged, broken off a bigger piece of rock
river rock
- round rocks that are along the edge & at the bottom of
fast-flowing rivers
stone
- medium, you could hold it in two hands
pebble
- small, you can hold it with two fingers, could get
stuck in your shoe, usually rounded
sand
- made up of tiny pieces of rock, grains of sand
grain
- tiny, like a grain of rice or smaller, often found on a
beach
The rocks you see around you - the mountains,
canyons & riverbeds, are all made of minerals
So . . . What is a MINERAL?
1. A solid NOT a gas or liquid
2. Naturally forming NOT man-made
3. Inorganic NOT living
4. A mineral is composed of the same
substance throughout - if you were to cut
a mineral sample, it would look the same
inside and out
90% of the Earth’s
crust are
SILICATE
minerals
Characteristics used in the
identification
&
study of minerals
1. Color – this varies depending on the
chemicals present and is the
least informative (reliable) in
identifying a mineral because it
can
change
or
the
same
mineral
Both of these
can come in a variety of colors
samples are the
mineral fluorite.
2. Luster –
What the surface looks
like in the light – is it
shiny or dull?
Scratching tools:
3. Hardness –
•fingernail (2.2)
•copper penny (3.5)
•pocket knife or common nail (5.2)
•piece of glass (5.5)
•steel file or concrete nail (7.5)
•piece of corundum (9)
What it can scratch
&
What scratches it
4. Cleavage - is when a mineral breaks with
smooth flat surfaces.
5. Fracture - is when a mineral breaks, but the
surface is not regular, does not show
cleavage.
6. Density / Specific Gravity –
how heavy it feels, heft
7. Tenacity - is how tough a mineral is, how
easily a mineral will break,
split, crumble or change shape.
8. Transparency - The ability to transmit
light.
•Transparent
•Translucent
•Opaque
9. Streak –
The color of the
mineral in
powdered form.
The mineral is
rubbed against a
piece of unglazed
porcelain called a
streak plate.