Rough Assortment | Planning and marking | Cleaving and Sawing | Bruting | Polishing
This is a very important department, as a diamond begins its journey of being transformed from a rough to a polished stone from here onwards. The work of this department is to check the rough stone and to determine its properties such as purity, color, & size etc. i.e. 4'C's namely color, clarity, carat, cut. Keeping all these 4Cs in mind they give the rough stone a grade.
Planning & Marking
This is also one of the most important phases of the entire manufacturing process. It can also be known as the brain department of the entire process. This is because in this department the person has to decide as to which shape the diamond shall finally assume and as to what is going to be its cut and its weight. Here the person doing the planning, after he plans as to what is going to be the final product, he has to mark the diamond from where the diamond is to be sawn or cleaved or to point out where top bottom table is to be kept.
Cleaving and Sawing
Cleaving and sawing are simple processes by which a diamond can be divided into 2 pieces. Now in diamond there are different planes on the basis a diamond that is marked can either be cleaved or sawn. If the marking is along with or parallel to its planes then the diamond has to be cleaved. Cleaving is simply done by a chisel and hammer, wherein the hardest material available is split into 2 pieces at the blow of the hammer.
If the marking is perpendicular or against the planes then the diamond needs to be sawn i.e. 'cut' Sawing in the recent times has advanced a lot as far as technology is concerned. Earlier sawing used to be done by sawing machines to cut the diamonds into 2 with blades. This was a very time consuming process usually taking hours to saw a diamond. This process is still very much practiced by the people world-wide. Currently laser sawing is the latest technology in sawing. The greatest benefit of this system is that, it is very fast and precise. A number of pieces can be sawed using laser technology at the same time by single equipment.
Once the process of Cleaving / Sawing is completed the diamond is sent back to the planning and marking department for checking the results of procedures and then passed on to the next process of Bruting.
Bruting is the process of giving shape to the rough diamond. A person doing this has to take care of many things as the rough diamond is of ' vivid ' shapes and resembles a normal stone. The bruter has to take its utmost care of the diamond at this process so that it does not break. Also in this process the bruter has to leave as much of natural skin on the piece of diamond as possible. This is because one can check out that the weight loss of the diamond in this process is not more than required. The minimum natural left has to be in a particular way, i.e. it has to be on the table as well as the bottom of the diamond. At the bottom of the diamond it has to be in 3 positions so as to cover the circumference of the diamond. In the whole process of Bruting the main aim of the bruter is to give a shape to the rough diamond in such a way that its optimum effect can be achieved by the polisher, without any extra weight loss than required.
After being bruted a diamond passes to the polishing department where the final work of faceting is done. Polishing means the process of giving the diamond its final look. Here the artisan has to be very careful at all stages as even a small mistake done by him can make the diamond look poorer than what it might have looked had it been cut properly. This is the last step in the manufacturing process of the diamond from where on it goes to the grading department.
Rough To Polish
A diamond is found naturally in the rough form. It looks much like a crystal and lacks any real luster. The true brilliance and fire of the stone is only unlocked after a number of processes described below. These processes can all be performed by different specialists.
The first step in diamond cutting is the examination of the stone in the rough form. Each stone is totally unique and so must be studied in detail in order to determine the finished shape that will retain as much weight as possible. The stone is then marked with India ink to indicate how it must be divided.
To cut a rough stone, it is first set in a 'dop' or holder using quick drying cement. Then, using another diamond, a small groove is made along the division line. A square-edged knife is then inserted into the groove and tapped sharply with a mallet. It is this action that determines the diamond's future as if the division line has not been placed properly, or followed accurately, the diamond can shatter. Cleaving is always done parallel with the grain of the diamond.
During this stage of the process, the diamond's girdle is formed. This is also known as girdling or rounding. The girdle is the band which is formed around the thickest part of the stone. To form the girdle, the stone is again set in a 'dop' which is in turn fixed on to the centre of a lathe which spins at high speed. Using another diamond set in a long 'bruting stick', the corners of the rough stone are gradually rounded off until the spinning diamond is perfectly round at its thickest part.
Blocking or Cross Work :
This is the final stage in the making of a polished diamond. It is during this time that the diamond's facets are polished onto the stone. This is done using a horizontally mounted circular cast iron disc known as a scaife. The scaife is of course impregnated with oil and diamond dust. The diamond to be polished is set in an adjustable dop at a certain angle and lowered onto the plate. The angle of the diamond must be changed for each facet.