| Judging
Clarity
Examining
Diamonds for Clarity
To
examine a stone for clarity you need a ten-power magnifier,
a lint free cloth, and a light source that allows light to
be directed through the sides of the stone. An ordinary fluorescent
desk lamp with a daylight type bulb will do. Tweezers or a
stonc holder is also helpful. Jewelers often use a hand magnifier
called a loupe . For those interested in owning a loupe, the
business section of the phone book has stores listed under
Jewelers' Supplies & Findings.
First verify that they have a fully corrected, ten-power,
triplet loupe. The loupe salesman or a jeweler can show you
some ways of holding and using it and help you select the
model that is the most comfortable and clear.
There
are a couple of guidelines you should remember about using
a ten-power loupe. Hold the loupe 1/2 to 1 inch (13-25 mm.)
away from the stone to bring it into focus. If you're examining
a large stone, hold the loupe close to one eye (about 1 or
2 inches or 25-50 mm.
from the eye) keeping both eyes open. The closer the loupe
is to your eye, the greater your field of vision is.
If
you're examining a lot of small stones less than 1/10 of a
carat, try holding the loupe further away from your face and
use both eyes to look at them. This will help prevent eyestrain.
The use of the loupe is not limited to the grading of gemstones.
It can also be used to judge the quality of fabrics or the
resolution of your computer printer.
It can even help you determine if the black specks in your
food are bugs or coarse pepper. Once you own a loupe you will
find lots of uses for it.When you have the necessary equipment,
you can proceed as follows:
1. Clean the diamond. Usually rubbing it with a lint-free
cloth is sufficient. Sometimes, though, you'll need to soak
it in soap and water or ethyl alcohol or even have it professionally
cleaned. Avoid touching the stone with your fingers as fingers
can leave smudges.
2.
Examine the stone from all angles with your naked eye. One
of the criteria for assigning clarity grades is the visibility
of the inclusions without magnification. Looking at the stone
first with a loupe can mislead you into believing inclusions
are eye visible when they aren't, because your mind has a
tendency to see what it expects to see.
3.
Examine the stone with a loupe from all angles. For viewing
inclusions, the light should pass through the side of the
stone; and for viewing surface blemishes, it should reflect
off the stone. Using a microscope instead of a loupe should
pose no problems. Most beginners even find it is easier to
use.
The
specks might
Decrease
the brilliancy
Book
has stores
Are
called pinpoints
Indentations
where chunks
There
are various
Allows
people throughou
Unaided
eye through
Grading
reports can
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