| F-J | K-O |
P-T | U-Z
Holes | Length-to-Width
Holes: one of the few man-made inclusions that can
occur inside a diamond. But why on earth would anyone want to drill holes into
a perfectly good diamond? It may seem counter-intuitive, but drilling this type
of hole into a diamond can actually raise its clarity grade. In some diamonds,
clarity is downgraded by the presence of just one or two dark included crystals.
In these circumstances, the diamond cutter might decide to use a procedure to
remove the dark inclusions in an effort to increase the clarity of the diamond.
First, he drills a precise hole, about the size of a pinprick, with state-of-the-art
equipment. Next, he forces a strong acid solution into the new hole. Since diamonds
are resistant to acids, the solution actually dissolves the included crystal while
leaving the diamond completely unharmed. The end result is a more transparent
diamond. The structural stability of the diamond is not compromised in any way
by this hole (usually detectable only by a microscope or a loupe), and the process
Ratio: a diamond is more long than wide and this ratio measures that relationship.
In this ratio, width is always represented by the value '1'. To determine the
value of the length, divide the millimeter measurement of the length by the millimeter
measurement of the width. These millimeter measurements can be found at the top
left-hand side of the diamond grading report. Length-to-width ratio is used to
analyze the outline of fancy sha
pes only; it is never applied to round diamonds.
There is no 'ideal' ratio; it's simply a matter of personal aesthetic preference.
a small magnifying glass used to view gemstones, usually 10x, or ten-power,
magnification. The FTC requires all diamond grading be done under 10-power magnification;
any flaws not detected under this magnification are considered to be non-existent.
Mounting (or Setting):
the part of a ring that holds the diamond(s) in place. It is usually made of gold
parts of the original rough diamond's surface that are left on the polished diamond,
frequently on or near the girdle. While these are blemishes, naturals may also
be regarded as a sign of skilled cutting; leaving a natural reflects the cutter's
ability to design a beautiful polished gem, while still retaining as much of the
original crystal's weight as possible. In many cases, naturals do not affect the
clarity grade. In most cases, they are undetectable to the naked eye. Another
type of natural is the Indented Natural; in this case, the natural dips slightly
inward, creating an indentation. Usually, the cutter makes an effort to cut the
polished diamond so that the indented natural will be confined to either the girdle
or the pavilion, making it undetectable to the naked eye in the face-up position.
Oval Cut: a type
of fancy shape diamond; essentially, an elongated version of a round cut.
on diamonds: A-E | F-J
| K-O | P-T