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 Cut
The cut refers to the angles and proportions of a diamond.
The cut of a diamond — its roundness, its depth and width, the uniformity of
the facets — determines its beauty. The skill with which a diamond is cut
determines how well it reflects and refracts light. A well-cut diamond will
internally reflect light from one mirror-like facet to another and disperse and
reflect the light through the top of the stone. This results in a display of
brilliance and fire. Fire, or dispersion, is the ability of a diamond to break
light into rainbow colors. Brilliance describes the brightness from reflections
of white light coming from the diamond.
Cut is considered to be the most important diamond
characteristic because a well-cut diamond can appear to be of greater carat
weight and have enhanced clarity and color.
The quality of the cut is determined by a number of
factors, including proportion, symmetry, and the relative angles of various
facets. The width and depth have the greatest effect on how light travels
within the diamond, and how it exits in the form of brilliance. A poorly-cut
diamond with facets cut only a few degrees out of alignment can result in a
poorly performing stone. A well- cut diamond should reflect most light out from
the table (the largest top facet) and make the diamond appear white when viewed
from the top. An inferior cut will produce a stone that appears dark at the
center and in some extreme cases the ring settings may show through the top of
the diamond as shadows.
  
The best cut diamonds have proportions that are within
specified ranges to maximize brilliance. The cut grading scale of diamonds is
based on the reflective properties of the diamond according to the calculated
diamond measurements.
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Super
Ideal:
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Approximately top 1% of
diamond quality based on cut for the utmost
brilliance, scintillation, and fire. These
diamonds have the highest grades of polish and
symmetry (Excellent or Ideal) to allow it to
reflect even more light than the standard ideal
cut. |
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Ideal:
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Exquisite quality cut to
create the optimal combination of brilliance and
fire. Reflects nearly all light that enters the
diamond. Top 3% of diamond quality based on
cut. |
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Very
Good:
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Superior
quality cut that reflects nearly as much light
as the ideal cut while at a substantially lower
cost. Top 15% of diamond quality.
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Good:
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Premium
quality cut to optimize the size without
sacrificing quality or beauty. Reflects most
light that enters. Top 25% of diamond
quality. |
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Fair:
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Good
quality cut which reflects some light while
maximizing weight. While not as brilliant as a
good cut, still a quality diamond. Top 35% of
diamond quality. |
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Poor:
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Inadequate quality cut that
reflects minimal amount of light. Brilliant
Earth does not provide diamonds with cut grades
of poor. |
Diamond
Characteristics
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Diameter:
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Width of diamond as measured
through the girdle. |
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Culet:
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The tiny
facet at the bottom tip of a gemstone. The
optimal culet should be pointed or very small
(graded “small” or “none”). |
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Table:
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The
largest facet of a gemstone, located at the
top. |
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Crown:
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The top
portion of the diamond, from the girdle to the
table. |
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Pavillion:
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The
lower portion of a diamond, from the girdle to
the culet. |
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Girdle:
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The
narrow rim around the widest part of a diamond,
separating the crown from the
pavillion. |
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Depth:
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The
height of a gemstone, from the culet to the
table. |
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