A myriad of people play important roles in the diamond value chain. Developing a diamond mine and selling the rough are activities that generate thousands of jobs in producer countries, and are a major contributor to many economies. Once a diamond is found, extracted from the ground, sorted, and sold, it enters the next phase on the diamond pipeline, the midstream, where it is polished.
Diamond manufacturing is a special section of the diamond industry, and the one that ultimately brings out the inherent beauty in these magnificent stones. Manufacturing employs countless people in countries all over the world. Most of these countries do not actually mine any diamonds at all. The process was once more art than science, but technology is changing this rapidly. Let’s take a look at some of the specialized occupations in diamond manufacturing.
Before most diamonds ‘hit the wheel,’ they must first be given a manufacturing plan. This ‘blueprint’ for the stone gives polishers the instructions on how to cut the stone, including the decision for the stone’s shape. This decision is a critical one, and is based on getting the maximum value for the finished gem. This process is the job of planners and markers. Before the sophisticated planning machines and computer software in use today, a marker did this job. The marker, who still has an important role to play today, gets his title because he literally marks the stone with a pen, indicating to others how the stone should be cut. Nowadays, planning machines have the ability to mark the stones with laser inscriptions, which adds another level of accuracy.
Today’s software helps make the job of the planner a little easier by doing many of the calculations for him. Ultimately, the decision to cut a stone one way or another comes down to maximizing value. The planner can use the computer to provide multiple scenarios and choose the one that generates the most valuable diamond. The planner must take many factors into consideration beyond just the ABCs of value. Different short- and long-term trends in consumer preferences, internal stress or weaknesses in the stone, or the presence of certain colors, can all impact his decision-making. For some large and high-value diamonds, the planning process can take months or even years to complete.
Some stones must first be cleaved or sawn before the manufacturing process begins. Again, these tasks have been fundamentally changed by technology, principally by laser cutting machines. In the past, cleavers would cut a small notch into the diamond and split it by applying blunt force, usually to a steel blade inserted into the notch. Cleaving is done along the grain of the stone to take advantage of the weaker crystal bond in this orientation. Sawing on the other hand is just that: the diamond is sawn into pieces. This process must go against the grain, using the strength of the diamond’s structure to avoid damage. Sawing used to be a very time-consuming process, using thin copper disks impregnated with diamond powder for cutting. It could often take 24 hours or more to saw a diamond, and machines had to be powered down during the process to replace the disks, which would get incredibly hot.
Today’s sawers and cleavers are almost entirely laser technicians. These machines have simplified diamond cutting, and have allowed for much more precision than was ever possible. Modern lasers can increase the yield of a stone by reducing the amount of material lost in the cut, and can also perform far more precise cuts, on different angles. Since these machines are expensive, and the technicians highly skilled, companies have developed to offer outsourced third party diamond-sawing services.
In most large manufacturing factories, diamond cutting is much like any other manufacturing assembly line process. Workers have one small but important task, which they do repeatedly to hone their expertise and efficiency. After each process, the stone typically goes back to a person doing quality control, to make sure that the diamond is on track, based on the planner’s initial modeling. Bruting is the first step, and requires a worker to put two stones together into a bruting machine, held in place with cement. The stones are oriented in the machine, which rotates them in opposite directions so that they rub against each other. This action rounds the diamond, and helps to establish what will become the girdle of the polished diamond. The worker must very carefully mount the stones to ensure that the proper shape is achieved, and that no unnecessary diamond loss occurs.
Once the stone is ready for polishing, it will typically go first to a ‘crossworker’ for blocking. Blocking is where the main shape of the stone is established, and the major table, crown and pavilion facets are applied. This will give a good estimate of the final expected weight, yield, and proportions of the stone. The finer detail of the stones facets is done by the ‘brillianteer,’ who finishes all the facets of the diamond. At larger facilities, a polisher will complete his or her particular part of the stone, before it goes back to a QC person to check the progress and make sure everything is working properly. Of course at smaller businesses, this work might all be done by the same person, or a smaller number of them, but the assembly line procedures are very similar.
Once a stone is complete, it will go for a final QC inspection, and a cleaning process in acid. Once the finished stone is ready, its future path will vary. Some stones will go directly into a piece of jewelry, while others will be sold as a standalone polished stone. I will look at some of the professions in polished sales next week.
The views expressed here are solely those of the author in his private capacity. No one should act upon any opinion or information in this website without consulting a professional qualified adviser.