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Fancy Color Diamonds

In the finest diamonds, the girdle is perceived as perfectly flat and parallel to the table.

The girdle will create a less than desirable wavy shape if the diamond cutter fails to properly angle the facets that meet the girdle.

In a perfectly cut round-cut diamond, the top point of the pavilion and the bottom point of the bezel facets align perfectly at the girdle. Any miscalculation resulting in misalignment is considered undesirable.

The positioning of the table, a diamond’s biggest facet, where white light enters and exists the stone, is best when centered at the top of a diamond while remaining parallel to the girdle. Uneven positioning will result when the table is off-center or unparalleled in relationship with the girdle. A table positioned in an off-centered way will results in an erroneous, off-centered look.

To determine if the culet is off-center, imagine 2 lines intersecting at the point of the culet viewed face-up. If the resulting four triangles are asymmetrical, then the culet is off-center. If the four triangles are perfectly symmetrical, then the culet is centered.

These can be found at any point on the diamond but typically appear on the pavilion, or close to the girdle. Extra facets usually occur when a diamond cutter attempts to remove or disguise an imperfection or natural by removing an external inclusion. Although the inclusion is disguised or removed, the diamond’s symmetry and light performance are compromised.

If the crown angle of a diamond is not perfectly parallel with its girdle, the table is perceived as off-center and undermining the symmetry of the diamond. Symmetry is very important for the light performance or brilliance of a diamond.

When a portion of the original rough surface of a diamond has not been polished, this is referred to as a natural. On occasion, naturals are left on the girdle and result in a heavier diamond. Naturals tend to dip towards the crown or towards the pavilion in most cases.

Please Note: Naturals, in essence, do not add size or beauty to the visible eye but rather add to the price.

A perfectly cut Round brilliant diamond best displays all 58 facets to perfection. Sometimes, however, the facets are improperly pointed and because of this fail to meet at a specific point.

A perfectly proportioned table will show an octagon shape of equal sides that are parallel to one another. This diagram displays a table that lacks symmetry due to the improper cutting of the facets.

Diamond Polish

Polish refers to the smoothness of individual facets of a diamond as measured by a trained gemologist. The finer the polish, the easier it is for light to pass through the stone. Microscopic imperfections created by the polishing wheel will reduce the diamond’s overall brilliance. In order to obtain the greatest possible shimmer, with maximum light passing through the diamond’s facets, an excellent polish is required.

Laboratory certification is helpful when purchasing a diamond. Make sure to select one with good, very good or excellent polish. Any grade below good, such as poor, is not recommended as microscopic imperfections created by the polishing wheel will reduce the amount of reflected light. One might wonder why a good diamond would possess a poor polish, and the answer is simply cost cutting. Excellent polishing requires more time and the greater the time involved, the greater the diamond cutter’s cost.

Grading Polish

Diamond polish and diamond symmetry are graded in a similar fashion.

GIA laboratories highest polish grade is Excellent, followed by Very Good, Good, Fair and Poor. AGS and IGI highest polish grade is Ideal, and followed by Excellent, Very Good, Good, Fair and Poor.

Under magnifications, the difference the various polish grades becomes more obvious. The lower grades, including Fair and Poor, suggest that the irregularities in the polish are visible to the unaided eye, thus reducing the perfection and beauty of the stone.


What is Diamond Fluorescence

Fluorescence is a naturally occurring phenomenon that a diamond displays when it is exposed to UV rays or black light. While wearing white, the same phenomenon or glow can be perceived under ultraviolet light. Similarly a diamond fluoresces when viewed under UV rays and approximately a third of all diamonds fluoresce to some degree.

How is Fluorescence Graded?

There are four distinct categories of fluorescence: faint, medium, strong and very strong, with subtle variations between the various categories. When a stone has a faint grading, its glow is barely visible under UV light. On the opposite end, a very strong grade means the stone has the deepest possible glow which is seen as crystal clear when viewed under UV light. The categories vary and the colors do as well, with green, yellow and white seen while blue most common of the four.

About Diamond Fluorescence

Florescence, in fact, is quite common. It appears in nearly 25% to 35% of all diamonds, with only a tenth of them visibly affected. These are noted on laboratory report as medium, strong or very strong. Almost all fluorescent diamonds are perceived by the naked eye as blue. On occasion a white, yellow green or other color may be seen.
No. Fluorescent and non-fluorescent diamonds have equal integrity. Substitutions too small to be seen under a microscope can both cause fluorescence as well as prevent it. In other words, fluorescence neither weakens nor is bad for a diamond.
Appearance is hardly affected by the strength of fluorescence. In fact, the majority of people are attracted to diamonds with medium to strong fluorescence. Stones with very strong fluorescence on rare occasions will appear fuzzy or oily. On rare occasions (less than 0.3%), fluorescence will exhibit such an effect.