How Diamond Is Made: Making Diamonds by Means of Cutting

Diamond has always been the most precious stone since ancient times. Diamonds are found under the earth, deep in the ground. Diamonds unearthed with modernized mining techniques from the past to the present are in raw form. Do you know how the diamond becomes the final product? To ask more specifically, how the diamond is made?

Diamond is made by cutting. It takes its final form after it is cut. The most important factor when valuing a diamond is the cut. It is the fourth “C” factor that affects the price of the diamond. Although all four factors are very important, a flaw in a diamond’s cut is more noticeable than a yellowish tint or even numerous blemishes. A diamond’s brilliance, good luminosity (fire), and brilliance (spark) all depend on its optical properties.

When cut in the right proportions and well polished, diamonds shine brighter than any clear stone. The cut grade of a diamond is made by analyzing the cut proportions and finish quality (symmetry and polish) of the diamond. In cut grading, the ability of the person who cuts the diamond is actually measured.

History of Diamond Cutting

Until 1300, the only diamonds known in Europe were “natural crystals”. These “natural crystals” had a shape and transparency that was very popular at the time. After the rhombic dodecahedron, the most popular shape was the octagon. These were not the only diamonds used in jewelry. Derivatives of these shapes, cubes, and planes were also used. A wooden or copper rasp coated with diamond dust was used to make several facets on rough diamonds.

Since the 15th century, diamonds began to come into fashion in Europe and symmetrically arranged diamonds were cut. The millstone technique covered with diamond dust was used. In the 16th century, masters cutting diamonds were able to cut diamonds in better proportions. First, they had to give the diamond the shape of two regular pyramids with square or rectangular bases. At that time, to a greater or lesser extent, the table part was obtained by polishing the upper end of one pyramid, and the culet part was obtained by polishing the upper part of the other pyramid. These dimensions were very different from cutter to the cutter.

The most common dimensions were: The size of the table had to be equal to half the width of the diamond in its center. The crown height had to be one-third of the average height, the cone depth had to be twice the crown height, and finally, the culet surface had to be equal to one-fifth of the table surface. This form of cut was very popular until the end of the 17th century. At the end of the 17th century, the round diamond cut was born. The creator of this cut was probably Vincenzo Peruzzi, but the name “Peruzzi Cut” was given to this cut only in the 19th century.

Back then, this cut was the most modern cut. Later, the diamonds were cut more roundly, but the same angles and proportions continued to be used. These sections became known as the “European section” and are still defined as the “old European section” today.

How Diamond Is Made With Different Steps in Modern Cutting

Mechanical chipping and rounding have only recently emerged in the diamond industry. This changed some concepts in diamond cutting. The rough diamond crystal first goes through the inspection of the “rough diamond marker”. This person in the production factory has great knowledge and experience about the ways in which the crystal found can be cut to obtain maximum profit. He has to decide the weight and quantity of stones to be obtained from rough diamonds.

It may be easy to decide on crystals with good shape and near spotless, but it is extremely difficult to decide on crystals with irregular shapes and a high percentage of additional crystals. The more ideally cut a diamond is, the more beautiful it will be. However, cutting to ideal dimensions can result in some weight loss, so many diamonds can be cut with little deviation from ideal dimensions. The most common change is to make the crown flat and the table part wider.

With deviations from ideal proportions, almost ten percent of the weight loss of the raw crystals is saved. Because the rough diamond pointer knows that the more unblemished a diamond is, the more valuable it is, so it examines the rough crystal under a 10x lens. It tries to determine where each blemish is on the diamond and aims to remove these blemishes until the diamond takes its final shape. A surface (facet) is carved on the rough diamond so that a person can see it easily. This surface is called the “window”. The diamond marker must decide on the cutting method and classify the crystal with one of the following classes:

Craftable Crystal

A whole crystal that is ready to be cut and shaped to become a diamond is called a “makeable crystal”. The diamond specialist will mark with black ink how the diamond should be cut.

Split crystal

A diamond that appears to have a slit plane and this feature is well defined should not be a problem, but a diamond with a poorly defined shape requires a long time to study and work on it. It may take days, weeks, or even months for a cutter to work out exactly where to cut a diamond (for very large or extraordinary diamonds, for example). Because if it is not determined exactly where the diamond should be split, the whole stone will be shattered. There are some cases where both chipping and splitting are done on the same diamond. This usually happens with larger diamonds where more splitting is required.

A diamond can split in the octahedral (eight-sided) direction, in other words, split in the “vein” direction. First, the diamond to be split is glued to the end of a stick called a “dop stick”, and a sharp diamond is glued to another stick. The sharp diamond is then rubbed along the ink track (and vein) that indicates where to cut the diamond. When a groove of the appropriate size, called a “kerf”, is made, a metal plate is inserted into this groove and an attempt is made to apply pressure to the walls of the diamond without touching the ground. The metal plate is then slowly pulled apart and the diamond splits in two.

Chipped crystal

A diamond can be chipped in many directions, the most common being the cubic and dodecahedral (twelve-sided) directions. The circular saw consists of a bronze disc with a radius of 7 to 10 centimeters and a thickness of about 1/10 mm. The saw rotates 4-7 thousand times per minute. A mixture of olive oil and diamond dust is applied to the edge of the saw. A chamfer is made into the diamond to make it easier to start the chipping process. The diamond is clamped in a vice and fed to the rotating saw. This way, the stains are chipped away. Because the chipping process takes so long, the chipper needs to check the saw frequently to make sure the process continues in the chosen direction.

More Detail on Modern Diamond Cutting Processes

When both the chipped and split crystals are of the appropriate size, the rolling process begins. The diamond to be rolled is glued to the end of a wooden stick and then attached to a rotating machine. The person doing the rounding shapes the diamond using a stick with a diamond attached to the end. The person who rolls the diamond (Bruter) is also known as the girdler. Because the belt part of the diamond is formed during this rounding process. A flat-arch cut diamond is not rounded, but polished.

The surface cutting or polishing of a rounded belt is done by the “blocker”. In “diamond cut” surfaces are added in two stages. After rounding, the diamond goes cross-cutter to cut the first eighteen faces. These surfaces; the table, which is the largest surface at the top of the diamond; four corners on the ground, four cones. The first surface carved after the table and culet part is sharpened is a corner on the floor. This is perhaps the most important part of the process. Because the first eight surfaces must be equal to each other in terms of size, and any mistakes made will be repeated on other surfaces.

The angle of this surface is critical relative to the arch. Because it is this angle that makes the diamond shine. To measure this angle, the “cross worker” has a special tool, but only with skill, experience, and dexterity can he tell whether the surface has been cut to the exact extent required. If he is satisfied with the result, he sculpts the second corner opposite to the first, followed by the second, third. The diamond is turned over, and the first top corner is chiseled directly above one of the floor corners, again to the predetermined angle. Then the remaining three corners are added. Afterward, the first bezel is carved at the junction of the two corners.

The size of the bezel should be well decided because when all four bezels are added, the tabletop should be a perfect octagon surrounded by eight equal surfaces. These surfaces are sometimes called “eights”. The diamond is turned over once again and the four cone faces are added directly down. The person who carves the diamond surfaces is called a stone blocker. The “Scaife” is a steel wheel thirty centimeters in diameter and about three centimeters thick, coated with diamond cream. The wheel rotates approximately 125 times per minute, and the diamond clamped securely in the vice is held in this wheel.

Blocker carves the table part, the culet, and the sixteen main surfaces (eight bezels and eight cones). The crystal structure of the diamond has a significant contribution to the chipping ability, and holding the diamond against the abrasive wheel is crucial. Before a diamond is chipped and polished, it must be ensured that the chipping direction is correct. With a defined diamond this is not a problem. The diamond should be chipped in the direction of the grain line. If the diamond is forced to chip outside of the grain, the final image will appear round because small pieces have been broken off.

Finally, a “polisher” polishes the last forty surfaces. It uses the same equipment as the stonemason, but with a better diamond cream and wheel to get a smooth and sparkling surface. There are also automatic polishing machines used. These machines polish diamonds very quickly and cheaply but are not of much use for larger and rarer diamonds. Although polishers are more effective, they cannot be compared to the experience and skill of a polisher.

Although the above-mentioned procedure is explained with the example of round diamond cutting, this procedure is the same for cuts of other diamond shapes such as marquise, pear, oval, heart diamonds. These figures apply to diamonds weighing more than one carat. Marquise, pear, oval, half-moon, are other varieties of diamond cut. The fifty-eight surfaces these diamonds have are not identical due to the bending of the belt. Emerald (cut), baguette, kite, triangle, epaulet, and Lorenzo are variations of the table part or step cut.

Diamonds cut in these shapes have fifty-eight facets, sometimes fewer. The same optical laws apply to cutting fancy figures. The only difference is that the diamonds are elongated by making the cross cuts different. Diamonds without circular belts may not look as bright as well-cut round diamonds. To achieve the best shine in a fancy diamond cut, it is necessary to keep the angle and ratio of the narrow cross-sections as close as possible to the angles and proportions ideal for cutting a round diamond.

The brightness of fancy shapes may decrease proportionally as they move away from the ideal cut. The “window” is a common mistake in emerald cutting. “Window” is a surface that a person can see when viewed from the table side of the diamond. Diamonds cut with a “step” cut or a “square” cut have a deeper cone than round diamond cut diamonds. In these deep diamonds, the shine and sparkle are lost due to the penetration of light.

How Diamond Is Made With Ideal Cut or “Tolkowsky Cut”

In 1916, E.F. Wade was the first to identify the different factors that would affect the beauty of a diamond while trying to maintain the maximum weight of the diamond while cutting. But Wade’s statement was never heeded. After that, in 1919 Marcel Tolkowsky worked on the cut of diamonds and published a paper called “Diamond Design”. In this paper, he listed the most important factors to consider when cutting a diamond that offers the best balance between scattering, brilliance, and sparkle.

In fact, what Wade did was calculate the most ideal proportions of a diamond based on the motion of light falling on it from all angles. Tolkowsky also developed a theory showing that small changes in the angle and orientation of diamonds can greatly increase the brightness of a diamond. Although this theory resulted in greater weight loss than raw crystal, the additional shine it would provide was enough to make it the line of the future. This modern Tolkowsky cut consisted of longer and narrower cone surfaces and a slightly wider table, and almost no culets.

Tolkowsky made the most of the optical properties of the diamond and thus discovered the modern “round diamond cut”. Today, however, the most brilliant-cut diamonds deviate slightly from these ideal proportions. It should be remembered that a diamond’s brilliance is not optimal unless its proportions are good and the angles relative to the belt plane approach ideal lines. These proportions are called the “American ideal cut” or the “Tolkowsky cut”.

The proportions of the ideal diamond cut proposed by Marcel Tolkowsky are as follows: The crown consists of 33 surfaces: a table, eight-star surfaces, eight bezel surfaces, and sixteen upper arch surfaces. The cone section consists of 25 surfaces, eight cone surfaces, sixteen lower arch surfaces, and one culet. The bezel angles at the crown are 34 ½o and the cone angles are 40 ¾o. The proportions of the ideal cut are made according to the average diameter of the belt. The diameter of the belt plane is equal to 100%, the table is equal to 53%, and the overall depth is equal to 60-61%, and the belt thickness can be between 0.7-1.7. The crown height is 16.2% and the cone depth is 43.1%.

As mentioned earlier, however, few diamonds are cut to Marcel Tolkowsky’s ideal proportions. This is due to an effort to gain maximum weight from the rough diamond. It is clear that most diamonds on sale today have marked deviations from ideal proportions in terms of table size and crown height. It is very possible to find table size diamonds with a belt diameter of 68-70%. Large-table diamonds are common, as diamond cutters try to avoid weight loss as much as possible.

However, a wide-table diamond may appear larger than an ideally cut diamond, but it has less sparkle. This design proposed by Tolkowsky has been generally accepted, but there are also dissenters among diamond experts regarding table size. A slight departure from Tolkowsky proportions in diamond cutting can be tolerated unless a decrease in gloss is detected by experts. Therefore, it is normally accepted to deviate a little from the standard measure within bounded lines.

The categories determined for the cut rating are listed as “very good”, “good”, “near good”, “medium”, “mediocre”, and “poor”. Major deviations from “Tolkowsky diamond-cut” proportions:

Bigger or smaller table size
Very steep or very oblique crown angles
Too thick or too thin belt
A cone that is too deep or too flat

These deviations are visible to the naked eye. A flat cone can result in a “pale” appearance in the center of the diamond, and as a result, the arch may be reflected in the center of the diamond when viewed from the tabletop. This is called “fish-eye”. A deep cone angle will cause the center to appear dark.

A change in the crown angle reduces the sparkle of the diamond. “Large” diamonds are common. These diamonds have tables wider than 60%. Such a small change will reduce the light scattering property of the diamond, thus reducing the brightness of the diamond. Increasing the size of the table to 67% or more or changing the proportions at the top of a diamond’s arch in the finishing process will result in a reduced shine of the diamond.

The proportional meter is a standard tool used in the IGI, but not essential for the person rating the diamond. The proportional calculation can also be done visually. Since the proportion meter can only be used on free diamonds, it is very important that the grader can also visually calculate the proportions of a diamond.

Other Variants of the Modern Diamond Cut

There are two different diamond cuts that are used very frequently today. These are “Practical Fine Cut” and “Scandinavian Standard Diamond” cuts.

Practical Fine Cut

This cut shape is the diamond cut shape chosen to be applied as a standard while evaluating the proportions in Germany. There is very little deviation from the Tolkowsky section. Some diamond cutters consider this cut to be a development of the Tolkowsky cut. Light from the bevel is also taken into account in this style of cut.

Table diameter: 56.0% of belt diameter
Crown height: 14.4% of the arch diameter
Cone depth: 43.2% of belt diameter

Scandinavian Standard Diamond Cut

Like the Practical Fine Cut, this type of cut is the result of experience gained through continued practice. The following measurements were obtained when the well-cut diamonds, which stand out with their brilliance and sparkle, were examined.

Table diameter: 57.5% of belt diameter
Crown height: 14.6% of the arch diameter
Cone depth: 43.1% of belt diameter