The cut of a diamond refers to its style and make. Style meaning the shape of a diamond and make meaning proportions and finish of a diamond.

Marking a rough diamond before the cutting procedure.

The shape you choose is really a personal preference or individual taste. The most popular shape and also the most brilliant is the Round Brilliant. Other popular choices are the Oval, Marquise, Pear, Heart, Emerald and two newer cuts becoming increasingly popular are the Princess and Radiant cut.

All of the traditional shaped diamonds have 58 facets. A facet being a flat polished surface on a diamond. While the newer cut Radiant, a square or rectangular shape, is cut with 70 facets and is almost as brilliant as the Round.

The different facets of a Round Brilliant cut diamond

When choosing a fancy shaped diamond, one of the first things you may notice is the overall shape or proportions of the diamond. For example when looking at two Marquise shaped diamonds, they may have completely different shapes due to the proportions in which they were cut. One may be very long and thin while the next shorter and wider. Whichever proportion you choose, it should have a pleasing effect to the eye. If it falls to far out of the normal proportion outline, it may start to loose some of the brilliance or have unplanned light leakage.

Proportion is the key to beauty, and it is the relationship between the size, shape, symmetry, weight distribution and angles of various parts of the stone. While finish refers to the exactness of the facet shape, placement and polish.

When judging the proportions of a diamond, here are a few key elements to keep in mind. These elements mostly refer to a Round Brilliant cut, but can also be modified for fancy shapes. A well cut diamond or an ideally proportioned diamond will allow the most amount of light to be reflected back to the eye and therefore, it will be brighter and very brilliant. If the diamond is cut too shallow it will lose light through the bottom of the stone, it may also show a whitish ring around the table which is referred to as a fisheye. This type of cut may make the diamond look larger because the top of the stone is spread. This does not contribute to the brilliance of the diamond. If a diamond is cut to deep, light is lost through the sides of the diamond. The diamond will appear very dark in the center, this is known as a nail head, and this also interferes with the brilliance.


The table size is usually referred to as a percentage of the girdle diameter. Today, table sizes are normally 55 - 65% of the girdle diameter. The table, which is the large center facet on the top of the diamond, forms a square. If the square seems to form straight lines or bows in slightly, it is generally in a acceptable range. The brilliance of a diamond comes directly from the table. Often to make a diamond appear larger the table will be made larger and the crown angles thinner, this will produce more brilliance and less dispersion. As some may call it, "more flash for your cash". If the table is made smaller and the crown angles steeper, you will see more dispersion and less brilliance. If you see a nice combination of brilliance and dispersion, the proportions are usually within an acceptable range.

The girdle is a narrow band which separates the crown from the pavilion of a diamond. The thickness of the girdle needs to be just thick enough to set the stone securely. If it is extremely thin (knife edge), it can be very brittle and vulnerable to chipping or breaking severely. If it is to thick it may add weight to the diamond, but not necessarily contribute to its beauty and being to thick may even create a large fuzzy gray reflection in the stone. The thickness of the girdle may slightly vary around the stone. A medium girdle would have a distinct line under 10X and would be a thin line to the unaided eye.

One last thing you may want to look at is the overall symmetry of the stone. Does the diamond create an even display of brilliance, dispersion and scintillation? Are the facets aligned or pointing properly? Keep in mind most diamonds have symmetry variations. There isn't a diamond that is perfectly round, or tables that are absolutely parallel to the girdle plane. For this reason, unless symmetry creates an obvious effect, it is usually considered a minor finish characteristic. If a diamond is being purchased for the sole purchase of enjoyment, it should have the overall qualities that will make you happy for many years to come.

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