Properties
included
in
Diamond
Reports:
Certificate
Number:
IGI
uses
the
terminology
"Diamond
Identification
Report"
although
it
is
recognized
as
a
certificate
.
Every
lab
has
a
certificate
(or
"report")
number,
which
identifies
a
diamond
uniquely.
The
Lab
keeps
an
internal
copy
of
everything
shown
on
the
certificate,
and
also
additional
information.
The
certificates
can
thus
be
re-issued
when
they
are
lost.
Shape
and
Cut:
Shapes
can
be
categorized
as
Round,
Pear,
Heart,
Oval,
etc...Cutting
Styles
can
be
categorized
as
Brilliant,
Marquise,
Emerald,
Princess,
Step
and
Mixed.
Measurements
:
Measurements
of
the
Diamond's
diameter
are
calculated
to
the
hundredth
of
a
millimeter
by
a
non-contact
measuring
device
or
a
micrometer
which
is
defined
as
"
minimum
-
maximum
x
depth
".
Carat
size:
Diamonds
are
weighed
to
the
thousandth
of
a
carat
with
a
digital
measuring
device.
On
the
Report,
the
weight
is
rounded
off
to
the
hundredth
of
a
carat.
Proportions:
The
proportions
of
the
diamond
can
be
the
summed
up
as
its
depth,
and
its
table
.Both
are
expressed
as
percentage
figures.
Depth
percent
refers
to
the
percentage
depth
of
the
Diamond,
measured
from
the
table
to
the
culet,
relative
to
the
width
of
the
stone.
The
Table
of
a
Diamond
refers
to
its
largest
facet,
which
is
the
main
part
of
the
Diamond
you
look
at
when
the
stone
is
face-up.
Table
percent
refers
to
the
table
size
expressed
as
a
percentage
of
the
Diamond's
average
width.
These
ratios
determine
how
well
a
diamond
has
been
cut.
Girdles:
The
Girdle
of
a
Diamond
is
the
border
between
the
crown,
or
uppermost
part
of
the
stone
and
the
pavilion,
and
bottom
part
of
the
stone.
Girdle
thickness
is
usually
expressed
as
a
range
since
it
can
vary
from
thin
in
one
part
to
thick
in
another
part
of
the
diamond.
The
girdle
can
also
be
faceted.
A
faceted
girdle
usually
enhances
the
look
of
the
stone,
and
includes
polished
facets
into
the
girdle.
Below
are
example
Girdle
Thickness.
Culet:
The
Culet
of
a
Diamond
is
the
facet
on
the
pointed
lower
part
of
the
Diamond.
Its
existence
helps
prevent
chipping.
Some
diamonds
don't
have
a
Culet.
Finish
,
Polish
&
Symmetry:
Finish
expresses
the
polish
of
a
Diamond
and
the
symmetrical
,
and
evenness,
in
the
placement
of
the
facets.
Polish
refers
to
the
quality
of
the
polish
given
on
the
facets.
An
excellent
polish
shows
the
care
and
precision
of
the
Diamond
cutter.
Symmetry
refers
to
how
precisely
the
facets
are
aligned
to
each
other.
Clarity:
Clarity
ranges
from
the
best
grade
of
IF,
down
through
VVS1,
VVS2,
VS1,
VS2,
SI1,
SI2,
I1,
and
I2
until
I3.
Clarity
expresses
the
number,
size,
placement
and
nature
of
inclusions
and/or
surface
irregularities
on
the
Diamond.
The
experienced
Diamond
Grader
at
IGI
examines
the
Diamond
with
the
aid
of
an
IGI-Microscope,
which
aids
in
identifying
the
nature
of
inclusions,
and
finding
pinpoints
(very,
very
tiny
crystals
inside
the
Diamond).
The
actual
grade
is
decided
only
on
what
is
visible
under
a
10X
magnifier.
Color:
Color
ranges
from
the
best
grade
of
D,
down
to
Z.
After
Z
we
approach
the
Fancy
Color
diamonds.
Color
grades
are
determined
by
comparing
the
diamond
with
a
set
of
excellent
grade
stones
under
special
lighting.
Fluorescence:
Fluorescence
refers
to
a
diamonds
reaction
when
exposed
to
long
wave
ultraviolet
radiations.
Too
much
fluorescence
can
make
a
Diamond
less
desirable.
Plot:
A
Plot
is
a
graphical
representation
of
the
imperfections
present
in
the
Diamond.
Every
diamond
has
unique
characteristics
like
fingerprints.
By
plotting
its
characteristics,
and
combining
this
with
the
physical
measurements
of
a
Diamond,
a
Lab
can
uniquely
identify
each
stone.
This
plot
is
a
guideline
for
the
Grader
in
the
event
that
a
customer
returns
to
the
Lab
and
requests
verification
on
his
diamond
purchase.
Internal
characteristics
are
plotted
in
red,
and
external
characteristics
are
plotted
in
green.
Comments:
Comments
are
used
to
describe
characteristics
which
are
not
discussed
elsewhere
on
the
certificate,
or
to
mention
the
items
not
plotted
or
shown.
For
example,
"insignificant
external
details
are
not
shown"
is
one
of
the
common
comments.
All
the
keywords
in
the
certificate
details
such
as
clarity,
cut,
color,
carat,
measurement,
size
etc
can
be
searched
at
our
bulletin
board.
