Transcript What is a mineralx

WHAT IS A
MINERAL?
Chapter 3: Minerals
A MINERAL DEFINED
 They are the building blocks of the crust of the Earth!
 Many are essential in a healthy diet. Remember the doctor always
says to “take your vitamins and minerals” to stay healthy!
 All minerals share these 5 characteristics:
 Naturally occurring: mother nature makes minerals…not us!
 Inorganic: made of things that are not living and never will be living!
 Solid: hard and breakable, with the exception of mercury which is a
liquid
 Definite chemical composition: unique combination of elements
 Crystalline structure: repeating pattern of atoms that creates
crystals
A MINERAL IDENTIFIED
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All minerals have certain traits that
make them different from all the
others
There are 5 traits you can test to
help you correctly identify a mineral
sample
1. Color
2. Hardness
3. Streak
4. Cleavage/Fracture
5. Luster
COLOR
 Color is okay to look at
initially, but you can not
base your decision only
on that one trait
 Why? Because a lot
of minerals look very
much the same!
 If we only looked at
color, we would not
identify it correctly.
Which of these samples is
calcite and which sample
is halite?
CAN YOU SCRATCH IT?
 When you try to scratch a
mineral, you are testing its
hardness
 If it can be scratched, then it is
softer than the object you used
to scratch it
 If it cannot be scratched, then it
is harder than the object you
used to scratch it
 Common minerals and their
hardness are ranked on Moh’s
Hardness Scale, listed from
the softest to the hardest
WE HAVE A STREAKER!!
 The streak of a mineral is the mineral in its powdered form
 Minerals will only have a streak if they are softer than the
streak plate (which has a hardness of 7)
 If the mineral has a metal in its chemical formula, it will usually
leave a streak
 The streak color will not always be the same color as the
mineral…so don’t assume!
I NEED A BREAK!!!
Cleavage and fracture
are two terms used to
describe how a
mineral breaks
Cleavage means it
breaks with smooth,
flat surfaces
Fracture means the
mineral breaks along
jagged surfaces
OH, HOW IT SHINES!
How a mineral shines
describes its luster
 If it shines like a metal, it has
metallic luster
 If it does not shine like a
metal, it has nonmetallic
luster
1. Dull
2. Earthy
3. Pearly
4. Waxy

OTHER NEAT PROPERTIES
Magnetism (magnetite)
Double refraction,
double image (calcite)
Fizzes when acid is
placed on it (calcite)
Fluorescence (glows
under a black light)
Specific gravity: THE
BEST TEST TO HELP
YOU IDENTIFY A
MINERAL!