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All About Round Diamonds

A Diamond Cut Above - The Round Diamond Shape Is By Far The Most Popular

The Round Brilliant Cut Diamond

Round Diamonds

All About Round Diamonds

When purchasing a diamond, you will undoubtedly hear much about the importance of its cut. There are many different types of diamond cuts available today, but a Brilliant Cut is so called because of the numerous facets that give the stone its exceptional brilliance and fire.

Interestingly, the shape is actually cut like that of a cone, which gives maximum light return through the top of the diamond, making it sparkle in a highly distinctive way.

Today the Brilliant Round is by far the most popular diamond cut of all. Its history reflects the fascinating evolution in jewelry tastes and technological innovation throughout the ages in the art and science of diamond cutting.

History of the Round Brilliant Cut

So what is the Round Brilliant Cut and why is it so universally admired and treasured? The Round Brilliant Cut evolved gradually over the centuries as new ways of cutting diamonds came into vogue. Throughout history, the diamond has been treasured for its relative rarity, brilliance and beauty.

Back in Roman times it was discovered that a diamond could actually be polished and cut with its own dust. In fact, the first “diamond cut” recorded was a simple polishing process in which the rough stone was shaped into an even, pointed eight-faceted structure. This “Point Cut” became the standard for over a thousand years and was universally used all over Europe.

By 1375, records show evidence that there was a full-scale diamond polishing guild in Nuremburg, Germany. In the 1400s, a new cut had been developed – the Table Cut. In addition to the usual polishing, diamond cutters now sliced off the top section of the stone to reveal a flat surface, or “table”. Soon jewelers were also cutting off the corners of the octahedron shaped stone, adding the first “facets” to its surface. This became known as the Old Single, or Old Eight Cut.

In the middle of the 16th century, Belgian traders unveiled an innovative new cut which looked like a rosebud unfurling; it was aptly named the “Rose” Cut. This completely changed any preconceived notions about the possibilities of what a diamond would or could look like. The Old Mine, or Old Miners’ Cut was first developed in the early 1800s and continued to be used well into the 1870s. Even though the Old Mine style came into being during the height of the Industrial Revolution, the vast majority of Mine Cut diamonds were cut entirely by hand.

Old Mine Cuts possess a distinctive cushion shape that mimics the original shape of the rough stone. They are shaped into a high crown with a small table, a round to somewhat rectangular girdle, a deep pavilion and a large faceted culet.

The Old European Cut

Old European Cut Diamond vs. The Traditional Round Brilliant Cut Diamond

Old European Cut Diamond vs. The Traditional Round Brilliant Cut Diamond. Photo courtesy of LangAntiques.

The Old European cut was another evolutionary stage in the path of progression towards the cuts of today and dates back to the 1800s. You will see it predominantly on jewelry produced during the Victorian, Edwardian and Art Nouveau eras. In general, Old European Cuts are described as having small table facets, heavy crowns and “deep” proportions plus a circular girdle. With 58 facets, it is the precursor to today’s modern Round Brilliant. The GIA has a special classification for Old European Cuts which must have a table size less than or equal to 53%. The crown angle must be greater or equal to 40% and the lower half facet length must be less than or equal to 60%. The culet size should be “slightly large” or larger. As cutters continued to experiment with proportions and diamond symmetry, there were many incremental steps between the Old European style and the modern Round Brilliant.

Transition Cut

Transitional Cut Diamond versus a Round Brilliant

Transitional Cut Diamond versus a Round Brilliant

Also known as the Early American Cut and the Early Modern Cut, this style had a lower crown, larger table, shorter pavilion and smaller culet than the Old European, though cutters had not yet begun to facet the girdles of the stones. Henry Morse operated the first diamond cutting factory in America, and was perhaps the second most significant diamond cutter after Marcel Tolkowsky. Morse’s jewelry shop in Boston was the first to consistently cut stones for their beauty rather than their size. His diamonds came with smaller tables, shallower crown angles and much smaller culets than the prevailing European Cut. The Transition cut appeared from around 1918 through the mid to late 1920s.

The Tolkowsky Ideal Cut

Tolkowsky Ideal Cut Round Diamond

Tolkowsky Ideal Cut Round Diamond

The original Round Brilliant Cut was developed by Marcel Tolkowsky with the publication of his 1919 thesis called “Diamond Design: A Study of the Reflection and Refraction of Light in Diamond.” Tolkowsky’s work described the ideal proportions of a round cut diamond for maximizing light return (or brilliance) and dispersion (or fire.)

The original Tolkowsky specifications (53% table, 59.3% depth, 34.50 crown angle, visible culet) have since been modified as the mechanics for round diamonds have been perfected over time. These exact cutting proportions, known as the Tolkowsky, the Modern Brilliant, or the American Ideal, became the standard for American diamond cutters. The Round Brilliant Cut consists of 58 facets (or 57 if the culet is excluded), ordinarily today cut in two pyramids placed base to base: 33 on the crown (the top half above the middle or girdle of the stone), and 25 on the pavilion (the lower half below the girdle.) In recent decades, most girdles have become faceted. Girdles may have 32, 64, 80, or 96 facets but these are not calculated in the total. While the facet count is standard, the actual proportions (crown height and angle, pavilion depth, etc.) are not universally agreed upon, so several different versions exist, including the Scandinavian Cut and American Cut.

“Branded” Cut

Some companies have come out with their own branded cut round diamonds. These are considered Modified Round Brilliants because they may have more facets than the traditional 58 facet Round Brilliant as originally designed by Tolkowsky. This makes it extremely difficult to accurately compare a normal 58 facet Round Brilliant with a standard GIA or AGS grading report to a branded cut diamond, because it is not a true “apples to apples” comparison. The branded diamond may have more facets but that does not mean it is a better quality diamond. We generally recommend our customers refer to a stone’s official GIA or AGS grading (see our advanced clarity chart), and try to avoid being swayed by marketing hype which can surround a special “branded” cut.

Hearts and Arrows Cut

In the 1980s, a new description for the effect of a Round Brilliant Cut was announced. Japanese jewelers were the first to discover the existence of a kaleidoscopic effect when a round brilliant cut diamond was examined through a special viewer. When looking from the crown or top of the stone through a kaleidoscope viewer there should ideally be eight symmetrical arrows. When looking through the pavilion or bottom of the stone there should be eight symmetrical hearts. The symbolism and marketing advantages of promoting these shapes, particularly in an engagement ring, are obvious, however it takes an extreme level of precision to achieve a perfect Hearts and Arrows patterning; for this reason, they are often called “super ideals.”

A “super ideal” Round Brilliant Cut will have exceptional light performance and precise optical symmetry. Again, buyer beware! Not every diamond with an excellent cut rating (GIA) will automatically mean it is a Hearts and Arrows stone. Jewelers tend to use the term loosely, so you should ask for paperwork to prove its H&A quality (ASET, Idealscope, H&A images)

A pure quality Hearts and Arrows stone is exceptional, and will likely be expensive. For this reason there are specific criteria that must be met to prove the quality of a Hearts and Arrows stone. They are:

Hearts and Arrows Diamond

Hearts and Arrows Diamond

  • There should be 8 regularly shaped hearts and 8 regularly shaped arrows, both with an identical intensity, so that each one is as pronounced as the other.
  • There should be no coloration of the hearts.
  • Both hearts and V-tips should be mirror images and symmetrical with each other.
  • The shafts of the hearts should be aligned with the points of the arrows and there should be a gap between every heart shape and the V-shape at their bottom.
  • The gaps between each of the 8 hearts should be equal, with no variation between the shoulder width in the hearts; the V-shapes at the bottom of the hearts also need to be symmetrical, with a correct alignment for each arrow head and shaft.

The Circular Brilliant

Circular Brilliant Diamond vs Round Brilliant DiamondSo what is a Circular Brilliant Cut? At the risk of further confusing the consumer, it is really a new name for an antique stone that slipped through the grading cracks established by the GIA. It is an older-style diamond that isn’t strictly Old European, but also was not cut to meet modern standards.

Previously, GIA graders had to decide whether to call this stone a Round Brilliant and grade it according to contemporary standards, or to call it an Old European Cut and simply record color and clarity without a cut grade. If you had a stone like this prior to 2013, it might have received a “Fair” or even “Poor” grade. The GIA agreed to create a new category for round 58 facet diamonds, under pressure from dealers who felt that these antique stones were being given short shrift. This new category is called the Circular Brilliant Cut.

The parameters are that the Circular Brilliant must have a lower-half-length less than or equal to 65%, the star must be less than or equal to 50% and the culet size must be medium or larger. These three criteria must apply for the diamond to be designated as a Circular Brilliant on its GIA grading report. This classification acknowledges that the diamond is not a modern-day Round Brilliant and keeps the historic Old European Cut definition unaltered.

Popularity and Price of the Round Brilliant

So now we’ve taken you through a little of the history and evolution of the Round Brilliant Cut. It is still to this day an exceptionally popular diamond shape and represents approximately 75% of all diamonds sold. Not surprisingly, it is a universal favorite with couples getting engaged but also for rings of all types and for all occasions. Because of the special mechanics of its faceted shape, which throws off spectacular brilliance, the round diamond is considered superior to other fancy diamond shapes. While the demand for Round Brilliant Cut diamonds is very high, their yield is lower because more of the rough stone is lost in the cutting process; the cost of each carat retained after cutting is therefore higher. A typical round diamond (for example; a 1.00 carat, F-color, VS2-clarity, Ex. cut) may cost 25-35% more than a similar fancy shape. In spite of this, the round brilliant continues to far outsell other diamond shapes.

In the past thirty years, the buying public has become vastly more educated about diamonds. More and more consumers expect a diamond report with their significant diamond purchases, and place a far higher priority on better proportions, better cut and more brilliance.

As far as round diamonds go, you can’t go wrong with a triple excellent cut round brilliant diamond.

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