way a diamond is cut, its width, depth, roundness, size
and position of the facets determine the brilliance of the
stone. Even if the color and clarity are perfect, if the
diamond is not cut to good proportions, it will be dull
and less impressive to the eye.
Flat, top facet of the diamond.
portion of the diamond, above the girdle.
that separates the top and bottom of the diamond. This is
the widest part of the stone.
Bottom portion of the diamond, below the girdle.
tip of the bottom of the diamond. This is the most fragile
piece of the stone.
widest part of the diamond as measured by the girdle width.
height of the diamond measured from the table to the culet.
The table of a diamond has a very important influence on
the overall brilliance of the stone. The best cut diamonds
have a table that is 56-62% of the size of the girdle diameter.
DIAMETER AND THICKNESS
The basis for checking the overall proportions of a diamond
is the diameter of the girdle, the part that separates the
top (crown) and bottom (pavillion) of the stone. All other
measurements are related as a percentage of the girdle diameter.
very few round diamonds are absolutely round, the girdle
diameter is measured in at least four directions, with the
highest and lowest values reported on grading reports. You
may see the Measurements section of a grading report look
something like this: 6.44 - 6.46 x 3.85 mm. This means that
the girdle is 6.46 mm at its widest point, and 6.44 mm at
its least widest point. The third number represents the
Depth of the diamond, which is the measurement from the
top of the table to the culet.
The pavilion is the bottom portion of the diamond, below
the girdle. The height of the pavilion greatly contributes
to the diamond's overall brilliance. If the pavillion is
too long or too shallow in proportion to the rest of the
diamond, light will "leak" out from the bottom
of the stone resulting in a duller looking diamond.