Colorless Diamonds > Round Cut

Round Cut
Round Cut
Round Cut Diamond Ring
Round Cut Diamond Ring.


Round Cut Diamond


The most popular diamond shape is the round brilliant cut. Carefully refined over nearly 100 years to maximize light return and sparkle, this shape has proven the test of time as a sought after choice. Almost three quarters of all diamond engagement rings feature a round brilliant diamond. Due to the mechanics of its shape, the round diamond is generally superior to fancy diamond shapes at the proper reflection of light, maximizing potential brightness. Virtually all round diamonds are brilliant cut, meaning they have 58 facets (57 when there is no culet).

Clean, classic, versatile and with more fire and brilliance than any other shape, it would be difficult to persuade anyone against this choice, as proven by the fact that it accounts for more than half of all diamonds sold today. (For men wishing to surprise their ladies and unsure of what they might like, one could hardly go wrong here).

Round Brilliant Diamonds


The Basics


Also referred to as: TOLKOWSKY IDEAL CUT


Round Cut Diamond Basics


Round Cut Quick Guide


Unique Features

Considered to be of ideal proportions to maximise brilliance and fire

Facets

58 (57 if culet pointed)

L/W Ratio

1.00 - 1.02

Origin

17th Century Mazarin

Expert Tip

Most brilliant and popular of all shapes; versatile and classic




Features



Round Cut Diamond Features

The round brilliant cut is the most popular diamond shape, accounting for more than half of all diamonds sold today. Although developed in Europe, the round brilliant is sometimes referred to as the American Ideal Cut.

With 58 facets divided amongst its crown, girdle and pavilion and a typical ratio between 1.00 and 1.02, it yields maximum shine as the cut naturally follows the rough diamond crystal.

The round brilliant is the most researched cut in the industry; for over a century, diamond cutters have used advanced scientific theories of light reflection and precise mathematical calculations to optimize its fire and brilliance.

Expert Advice


The round brilliant is the most versatile of all cuts both in terms of style and value. With more fire and brilliance than any other shape, this cut offers the ideal balance between cut, color and clarity grades and budget.

For a bachelor unsure of what might please his lady, it is hard to go wrong with this classic choice.

Round diamonds cost more on a per carat basis than fancy shapes for two reasons; the demand for round diamonds is very high, and the yield is relatively low. Because more of the rough stone is lost in the cutting of a round diamond, the cost of each carat retained is 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.

The round diamond began to rise in popularity in 1919 with the publication of Marcel Tolkowsky's thesis "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 cut mechanics for round diamonds have perfected over time. These theoretical advancements, as well as advancements in technology (such as the use of lasers in diamond cutting), have been adopted by diamond manufacturers to produce the incredibly brilliant cuts we see today in well cut round diamonds.

The table below serves as a general guideline for evaluating the cut of a round diamond. GIA takes these and other factors into consideration when assigning a cut grade:

Round Diamond - Cut Guide



Round Cut Excellent Very Good Good Fair Poor
Depth % 60 to 63 58 to 64 57 to 65 56 to 67 >56 or <67
Table % 53 to 58 52 to 62 51 to 65 50 to 67 >56 or <67
Symmetry Very good to excellent Good to excellent Good to excellent Fair to Excellent Poor to Excellent
Polish Very good to excellent Good to excellent Good to excellent Fair to Excellent Poor to Excellent
Crown Angle 34 to 35 32 to 36 30 to 38 29 to 41 <29 or >41
Pavilion Depth 42 to 44 42 to 44 41 to 46 39 to 48 <39 or >48
Girdle Thin to Sl. Thick Very Thin to Sl. Thick Very Thin to Thick Very Thin to Very Thick Ex. Thin to Ex. Thick
Culet None Very Small Small Medium > Medium
L/W Ratio 1.00 to 1.01 1.00 to 1.01 1.00 to 1.01 1.02 > 1.02


Evaluating color in round cut diamonds is subjective. Keep in mind that many customers may actually prefer the ever so slightly warmer colors of a G-H diamond over the cool colorlessness of a D-F diamond. In fact, most of the premium in price associated with round diamonds at the higher end of the color scale is driven by supply and demand; customers want the D-F color grades, and are willing to pay a premium to get them. In a world without diamond color grading, the price premium for higher grades would be much lower, as the actual differences in color are difficult to perceive. The color chart below provides a general guide for evaluating color in round diamonds:

Round Diamond - Color Guide



Round Cut Excellent Very Good Good Fair Poor
< .50 ct. D - G H - I J - K L - M > M
.51-1.0 ct. D - G H - I J - K L - M > M
1.0-2.0 ct. D - F G - H I - J K - L > L
> 2.0 ct. D - F G H I - J > J
Fluorescence None Faint - Med Strong Very Strong Very Strong


Like color, evaluating clarity in round diamonds is subjective. GIA provides excellent help with their clarity grades. Still, it is important to understand that each customer will have a unique standard for clarity. Some may be perfectly comfortable with an inclusion as long as they cannot easily see it. Others may insist on a more technically flawless appearance. The clarity chart below provides a general guide for evaluating clarity in round diamonds:

Round Diamond - Clarity Guide



Round Cut Excellent Very Good Good Fair Poor
< .50 ct. FL - VS2 SI1 - SI2 I1 I2 > I2
.51-1.0 ct. FL - VS1 VS2 - SI1 SI2 I1 - I2 > I2
1.0-2.0 ct. FL - VVS2 VS1 - VS2 SI1 - SI2 I1 > I1
> 2.0 ct. FL - VVS2 VS1 - VS2 SI1 SI2 > SI2


History & Background


The origins of the round brilliant cut can be traced back to the middle of the 17th century when diamond cutters began using more refined and complex ways of cutting diamonds. The early brilliant cuts were known as Mazarins, after their designer Cardinal Mazarin, who made the first cross-cut diamond in 1650.

Through a series of gradual transformations and developments over the course of the 18th century, the Mazarins gave birth to the Portuguese Peruzzi, "old mine," or "old European cut" in the 1700s.

It was not until 1919 that the early modern round brilliant was created; at the time it was referred to as the Tolkowsky cut named after its creator, Russian mathematician and diamond enthusiast Marcel Tolkowsky.


Round Cut Diamond History