this video shows you in part how rocks
are prepared for view under a microscope
we'll start with the oil saw this is our
technician bill he's clamping in the
rock in preparation for cutting it with
that circular saw blade it's important
that he clamps it in so the rock remains
steady as it's being cut the oil saw is
generally used to cut flat slabs from
bigger rocks rocks that are too big to
be cut on other saws he has to close the
lid to keep the oil contained
now he's turned on the saw blade and he
loosened the knob that will allow that
weight to pull the rock toward the blade
in order to cut it
you may notice the oil everywhere the
oil saw is called an oil saw because it
uses oil as a lubricant this stops heat
caused by friction from shattering the
blade or otherwise damaging it this saw
blade does not have teeth like a blade
that would be used to cut wood but
instead uses commercial grade diamonds
to grind down the rock so he's made one
cut but he still needs a flat slab so
he'll make another cut
here's the finished slab this part will
be cut down further the other parts of
the rock will be saved for different
analyses
for now he's going to wash the rocks
just to minimize mess in the lab we
don't want oil all over the other
equipment or on the tables so we even
put them in the dishwasher to get them
really clean
now bill is looking for features in the
rock he would like to see up close these
could be mineral alignments or other
clues that can help us figure out the
geologic history of this rock the
rectangle he's tracing around is what he
will cut out on the water saw this is
the water saw it uses water to cool down
the blade and to prevent dust from
becoming airborne this saw blade is
another diamond blade and does not have
teeth nonetheless bill is always careful
to keep his fingers out of its path
here's the finished product we call this
a billet it will be shipped off to a lab
and mounted on a glass slide to create a
thin section like the one seen here
geologists can look through a
petrographic microscope to see the
minerals that make up the rock the rocks
composition and its orientation may
provide clues about its formation in
history here's what a thin section looks
like under a microscope here's what it
looks like under cross polarized light
thank you for watching