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A
well-cut diamond is
sparkling and dazzling
and will reflect light
from one mirror-like
facet to another until
it bursts from the top
of the stone. This breathtaking
display of brilliance
is a combination of
artistry and optical
engineering which requires
precision and experience
from the cutter. A diamond
cannot only be cut for
size or carat weight,
which is why Spencer
& Spencer puts brilliance
first for all of our
diamonds.
Cut is critical to
the beauty of a diamond
not only because it
affects the interaction
between a diamond and
the light around it,
but because the way
a diamond is cut can
sometimes affect its
color and clarity.
Improperly cut diamonds
such as diamonds cut
too deep or too shallow
leak light through the
side or bottom of the
stone, resulting in
less brilliance and
value.
Since a round diamond
is symmetrical and capable
of reflecting nearly
all the light that enters,
it is referred to as
a “round brilliant”
because it is the most
brilliant of all diamond
shapes. It has 57 or
58 facets that when
perfectly aligned, work
in perfect harmony to
provide the most brilliance,
fire
and scintillation.
The cut or make of
a diamond is ultimately
graded by the quality
of its proportions
and finish
and are explained below.
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| A diamond’s
finish is the quality
of its polish and symmetry
as well as the condition
of its girdle and the
precision of its cut.
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| The
polish of a diamond refers
to the overall condition
of the facet surfaces.
The finer the polish,
the brighter and more
lustrous the diamond will
be. Because of its hardness,
a diamond will take and
keep the best polish of
any gemstone. |
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| The
symmetry of a diamond
refers to the exactness
of the alignment or placement
of facets. The symmetry
affects a diamond’s
ability to refract light;
therefore all facets should
be the same size and shape.
A symmetrical diamond
will have bottom pavilion
facets that match up well
with the top crown facets
and an even display of
brilliance, fire and scintillation.
Most diamonds have some
symmetry variations. |
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On
a diamond grading report,
the polish and symmetry
of the diamond are each
given a grade ranging
from Excellent (EX)
to Fair (F). The chart
below describes the
polish and symmetry
characteristics a diamond
usually would have depending
on the grade it was
given. |
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Very
hard to find polish
lines or tiny blemishes.
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One
or two tiny inconspicuous
facets. |
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Faint
polish lines or
insignificant blemishes |
Few
extra facets, slightly
misshapen facets.
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Slightly
transparent polish
lines on the crown,
small blemishes |
Table
or culet slightly
of-center, several
extra facets. |
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Obvious
polish lines on
several facets,
noticeable blemishes.
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Slightly
wavy girdle, slightly
off-center table
or culet, crown-to-pavilion
misalignment. |
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Polish
lines or blemishes
that reduce the
transparency. Usually
on diamonds with
low clarity grades.
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All
of the above under
10x magnification.
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| **Spencer
& Spencer does not
carry diamonds with poor
polish or symmetry. |
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Spencer
& Spencer uses the
following criteria to
grade cut, all which are
listed on your GIA or
EGL diamond grading report:
- Table percentage
- Depth percentage
- Polish and symmetry
- Girdle thickness
- Culet
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| The
chart below describes
some of the possible cut
characteristics round
brilliant diamonds would
have within the Excellent,
Very Good, Good, Fair
and Poor cut grades. |
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Perfect
alignment of crown
and pavilion facets,
small or no culet,
ideal depth, ideal
table. |
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Very
good alignment of
crown and pavilion
facets, small culet,
proportions resulting
in excellent brilliance. |
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Good
alignment of crown
and pavilion facets,
medium culet, proportions
resulting in good
brilliance. |
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Deep
or shallow pavilion,
possibly displaced
crown and pavilion
facets, medium to
large culet, slightly
off-center or small
table. |
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Shallow
or deep pavilion
resulting in light
leakage, irregular
girdle diameter,
off-center table,
truncated facets,
large culet, extremely
thick girdle, "fisheye"
or "nailhead"
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| **Spencer
& Spencer does not carry
diamonds with a poor cut
grade. |
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As
a light ray travels
into a diamond, it slows
down. When entered at
an angle, it bends and
travels through the
diamond, striking different
surfaces. This is called
refraction.
Some of the light that
leaves the diamond is
bright and white which
adds to the brilliance
of the diamond. Other
light rays divide into
colored flashes called
fire. Fire
is the result of the
separation of white
light into spectral
colors, or dispersion.
The spectral colors
are the colors of the
rainbow: red, orange,
yellow, green, blue
and violet.
When the diamond or
light source moves and
the diamond catches
the light around it,
it sparkles with flashes
of white and spectral-colored
light. This sparkle
is called scintillation.
Besides the diamond’s
optical properties,
scintillation depends
on the number and size
of the facets, the precision
of the facet angles
and the quality of the
polish.
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| Still
have Questions? You can
chat
live with a gemologist
Monday through Friday,
8am to 5pm PST. You can
also call us toll-free
at 800-406-4494 or e-mail
us at questions@spencer-spencer.com. |
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