| The cut of a diamond - its roundness, its
depth and width, the uniformity of the facets - all determine
a the brilliance of a diamond. Many gemologists consider
cut the most important diamond characteristic because
even if a diamond has perfect color and clarity, a diamond
with a poor cut will have dulled brilliance. |
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| The width and depth have the greatest effect
on how light travels within the diamond, and how it exits
in the form of brilliance. |
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| Too Shallow: Light is lost out
the bottom causing the diamond to lose brilliance. |
| Too Deep: Light escapes out the
sides causing the diamond to appear dark and dull. |
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| The diamond's proportions, specifically
the depth compared to the diameter, and the diameter of
the table compared to the diameter of the diamond, determine
how well light will reflect and refract within the diamond. |
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Diameter:
The width of the diamond as measured through the girdle.
Table: The largest facet of a gemstone.
Crown: The top portion of a diamond
extending from the girdle to the table.
Girdle: The narrow band around the widest
part of a diamond.
Pavilion: The bottom portion of a diamond,
extending from the girdle to the culet.
Culet: The facet at the tip of a gemstone.
The preferred culet is not visible with the unaided
eye (graded "small" or "none").
Depth: The height of a gemstone measured
from the culet to the table.
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Polish and symmetry are two important aspects
of the cutting process. The polish grade describes the
smoothness of the diamond's facets, and the symmetry grade
refers to alignment of the facets. With poor polish, the
surface of a facet can be dulled, and may create blurred
or dulled sparkle. With poor symmetry, light can be misdirected
as it enters and exits the diamond. The polish and symmetry
grades are clearly listed in each diamond detail page
and within the AGSL or GIA diamond grading report. For
the most beautiful diamond, look for a symmetry grade
of ideal (ID), excellent (EX), very good (VG), or good
(G) for an AGSL graded diamond, and excellent (EX), very
good (VG), or good (G) for a GIA graded diamond. Avoid
diamonds with symmetry grades of fair (F) or poor (P),
as the alignment of their facets may misdirect light so
severely that it affects the brilliance of the diamond.
Diamond measurements are calculated and applied to a cut
grading scale that makes it easy to understand how well
each reflect light:
- Ideal cut: Represents roughly the
top 3% of diamond quality based on cut. Reflects nearly
all light that enters the diamond. An exquisite and
rare cut.
- Very good cut: Represents roughly
the top 15% of diamond quality based on cut. Reflects
nearly as much light as the ideal cut, but for a lower
price.
- Good cut: Represents roughly the
top 25% of diamond quality based on cut. Reflects
most light that enters. Much less expensive than a
very good cut.
- Fair cut: Represents roughly the
top 35% of diamond quality based on cut. Still a quality
diamond, but a fair cut will not be as brilliant as
a good cut.
- Poor cut: This includes all diamonds
that do not meet the proportion standards of a fair
cut. These diamonds are deep and narrow or shallow
and wide and tend to lose most of the light out the
sides and bottom. Redford Jewelry does not carry diamonds
with cut grades of poor.
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- For the best value in a brilliant diamond, choose
a diamond with a cut grade of good or very good, and
polish and symmetry grades of very good or good.
- In an ideal- or very-good cut diamond with very
good or good polish and symmetry, consider less expensive
grades of color and clarity - look for a diamond with
G or H color and SI1 or SI2 clarity.
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