A diamond is born - Diamantschleiferei Michael Bonke

PondicherryThe small, idyllic city of Pondicherry (now Puducherry) is located in south-east India near the Bayof Bengal. The diversity of elements in this city and its surroundings is enriched by yet anotheraspect: a German company that cuts and polishes diamonds.In the first half of the previous century,Pondicherry served as a place of refugefor Indian freedom fighters, who searchedfor protection against the British; first andforemost, for Sri Aurobindo, the well-knownIndian philosopher.Pondicherry is special in more than oneways. It was first mentioned in Romandocuments in the first century annodomini. Excavations of glass beadsprove that at an even earlier time, it hadtrade relations with Egypt. Since 1673,Pondicherry was a French colony thatresisted the British, who had alreadytaken over the entire of India, asmuch as it could. Even today, visitorsare attracted towards the charmingelements of French architecture with itscatholic churches and colonial houses.

The international city of Auroville was established after Sri Aurobindo in the year 1968. It issupported and promoted by UNESCO and the Government of India. This, possibly the largest“Experimental Township” of our times with its futuristic ideas, architecture and social fabrics, issituated 8 km from Pondicherry. In the heart of Pondicherry and yet away from the hustle andbustle of the city, somewhat hidden under the palms is the premises of the diamond polishingcompany, aditi diamonds. Founded by Michael Bonke in 1981, it is till date 100% under privateownership. Housed in several wings of the building, 135 employees work here on an area ofapprox 1700 m2 and produce around 1000 diamonds every day. Legally speaking, aditi diamondsis a subsidiary of the diamond polishing company “diamantschleiferei michael bonke”.

diamantschleiferei michael bonke is currently the only German company, which still drivesthe diamond polishing business like a serious industrial trade. There are many companies inGermany, which claim to be diamond polishing companies. Most of them have as much to doto with diamond polishing as a used-cars dealer has to do to manufacturing cars. Of course,there are a few companies, which have actually employed one or two diamond polishers andundertake polishing or repair work. However, polishing diamonds cannot be very productive ifdone at a small scale. A family business with one to two polishers can never achieve the perfectionand profitability, which is within reach when you are working with more than 100 polishers. Thedivision of polishing in maximum 14 different production sections gives the polishers three majoradvantages:a) absolute perfection and precision in the procedure, in which the polisher is specialised.b) High speed and perfect routine in the specialised procedure.c) Minimum loss of weight of the diamond in the cutting and polishing process.As the polishers specialise in individual processes, different timings are set for individual operations.Thus, for example, only two table facet polishers polish enough table facets to provide about 40pavilion polishers with pre-polished, semi-finished diamonds. An industrially designed diamondmanufacturer has a minimum capacity of 100 polishers; productive specialisation is not possiblewith anything less than 100 polishers.Economic factors also drive a polishing company to maintain a minimum capacity. For example, ifa company cuts and polishes about 1000 diamonds per day, like we do, then it can also purchaserough diamonds in large quantities, either directly from a diamond mine or from purchasers inmining areas in Africa or South-America. Small handicraft businesses are forced to buy their stonesfrom middlemen, in which case the prices already increase by 5% to 10%. It is certainly indicativethat in the largest stock market of the world for rough diamonds, in the Antwerp Diamond Ring,there are only two German names that can boast of a complete membership: michael bonke anda North-German diamond dealer.

Out of 50 diamond-polishing companies, around 40 work with makables and only 10 with rawmaterial that can be sawed. Of these 10 polishing companies, only one company has its ownsawing plant. The reasons for this are relatively high investment costs and the difficulties arising tokeep your sawing plant running at full capacity. Our polishing plant has its own sawing departmentand is therefore technically far superior to standard competitors.Work on rough diamonds starts withsorting. After one lot of raw stonesarrives in the plant, it is sorted as follows:• Octahedron crystals,• Rhombo-dodecahedron crystal,• Flat stones,• Stones with special features.

The next work step is designing. This task is very important and full of responsibility. The resultof the cutting and polishing is largely dependent on this one small step. While designing, thesupervisor meticulously observes the diamond under a magnifying glass. Then he/she decideswhere the sawing cut can be made. A lot depends on the correct selection of the plane to be cut.It may happen that the cut has to go through an inclusion, which can then be cut away duringthe cutting and polishing process. Furthermore, the sawing cut must be such that after sawing,both halves must correspond to the ideal proportions of the brilliant to be polished. Another veryimportant decision is, whether a large and a small stone should be cut out of the rough diamond orwhether there should be two brilliants of the same size. This is usually a mathematical decision.Example:a 5.0 ct rough diamond is to be sawed. If it is cut in the middle, we will get two raw brilliants ofalmost the same size, i.e. of 2.45 ct each with a yield of 42%; this will result in two diamondsof 1.03 ct each. If the saw-cut is asymmetrical, then we would get one rough diamond of 3.0ct and one of 1.95 ct. These two cut brilliants would then have a weight of 1.26 ct and 0.82 ctrespectively. The sales returns of these two stones would be much lower than two stones of onewhole carat each.Another example:a rough diamond of 4 ct is sawed. If cut in the middle, it will result in two raw stones of 1.98 ct each,i.e. two brilliants of approximately 0.83 ct each. If the cut is asymmetrical, we will get a 2.5 ct stoneand a 1.46 ct stone. These two stones will yield two brilliants of 1.05 ct and 0.61 ct respectively.In this case, the asymmetrical sawing cut is more advantageous, because one diamond of onewhole carat (1.05 ct) and the other of a good half carat (0.61 ct) are worth much more than twodiamonds of good three-fourths of a carat (2 x 0.83 ct). So, such stones are cut asymmetrically.Even in case of very small stones, which yield only 0.01 ct after being cut and are barely the sizeof a pinhead, the designing must be done with great care. A careless designer can often cost thepolishing plant the entire profit for that stone.

GirdlingApart from setting the girdles, the method used to cut the given raw material to make a diamondis divided into three main processes:• Bruting (girdling),• Polishing the pavilion,• Polishing the crown.Depending on the number ofpolishers in a company, the mainindividual work procedures arefurther divided in several tasks.Bruting the diamond (after thesawing or cleaving of the rawstone) is the first big step. Theskill of the bruter determinesthe amount of weight that thestone will lose during cutting andpolishing.Therefore, this part of the workactually requires a lot moreconcentration than the actual cutting of the diamond. The owner of a polishing plant usually givesmore importance to its bruting department than other departments.As the first step, the sawed diamond halves are meticulously examined and classified in differentgroups. The section supervisor marks the stones in different colours using felt pens.

The perfect crystal-halves are marked in red and they go directly to the bruter. In case of unevencrystal-halves, they are first sent to a separate modelling department and there, four facets arecut on the side opposite to the sawing surface.With that the structure is later changed such that the stone easily fits in the bruting machine as perits own axis. Other diamond forms that deviate from the standard (e.g. so-called flats, i.e. stonesthat are too flat) go through specific individual treatment.During the actual bruting process, the stone is set between two axles that spin. The rotatingstone then grinds against another diamond (the bruting-stone). The bruting process continuesuntil the stone is perfectly round. The sawing surface is now a circular disc. The bruting surface,which is perpendicular to the sawing surface around the entire stone, will later become the girdleof the brilliant.If the bruter continues working recklessly, (whereby he/she can produce more stones per hour),it causes excess bruting and the stone loses too much weight. If the bruting is too less, then thegirdle might disappear later at some point during the cutting and polishing of the stone. In thatcase, the entire process for the stone has to be started afresh. Therefore, a lot of experienceand a great eye for distance are required to gauge the optimum dimensions for bruting. A brutermanages around 60 to 120 stones per day, depending on the size of the brilliant.

There are three types of girdles:• The bruted,• The facetted,• The polished.For all three types, the initial bruting process is the same. In case of bruted girdles, the girdleremains unchanged after the bruting. In case of the facetted and the polished ones, the girdlesare re-processed later when the stone is almost done. For the fire and the brilliance of the stone,it is not important whether the girdle is bruted, facetted or polished. Under normal circumstances,there is no incident light on the girdle inside the stone, which meets the observer’s eye. Brilliantswith facetted or polished girdles enhance its look only from the side and make it appear a littlemore perfect.

Table and pincettingTable facets are polished after the stone is round. The table facets are always on the sawingsurface of the diamond. Only the sawing surface is actually perfectly polished. This process doesnot take very long. A polisher polishes up to 450 table facets per day. For that, the stone is notfixed in a holder, but instead pressed into a tiny pot, which is filled with soft clay. It is then set onthe polishing skaif and searches for the right position that is parallel to the grinding disk. In thisprocess, the diamonds often fall out of the mini-pot and are hurled by the grinding disk across theroom. Therefore, the table-facet polishers always polish in a tiny room. Otherwise they would endup spending more time looking for the diamonds than polishing the table facets.After sawing, rounding and table polishing, the stones are sent to a pincetting department wherethey are fixed into the press-pots.The precision of the mini-spring collet is of great importance. If the stone is not sitting upright, thenthe culet, i.e. the end-point of the brilliant, moves away from the centre while cutting the pavilionand the stone loses its perfect symmetry. Although India has a huge diamond polishing industryand manufactures millions of press-pots daily, we import each individual pot from Belgium.Since, sometimes, the press-pot also gets cut along with the pavilion, and the fine edge holdingthe diamond wears out, we use one pot only once. We then sell these press-pots to other polishingcompanies, which use their pots up to ten times or more. The pots are sorted as per differentsizes in tenths of millimetres and must be adjusted as per the exact size of the stone.Pincetting, i.e. setting semifinishedbrilliants in pots, isan independent professionand requires just as muchattention as the polishingitself. There is one pincetterfor every six pavilionpolishers.

The pavilionIn the next work step, the pot with the fixeddiamond is inserted in the dop of the grindingnippers and the grinder cuts two wreaths offacets on the pavilion of the brilliant. Eightfacets that move towards the culet and 16facets that touch the girdle; the divisionof the facets around the culet is stoppedwith the help of a click-system on the dop.However, the polisher must monitor everyfacet using a magnifying glass during thepolishing process and constantly correct theangle manually, so that all facets are of theexact same size and the angles are perfect.Polishing the pavilion is the longest individualwork-step, and hence this department is alsothe largest. A polisher can manage up to 30to 40 pavilions per day. If the polisher doesnot cut the individual facets of the pavilionwith precision and at the same angle, thenthe girdle size becomes inconsistent. Thepavilion is then not exactly congruent withthe axis of the brilliant and the stone is notstraight. As a result, the incident light is notreflected directly back to the light source,but is scattered instead.Completing the work on the pavilion is onlythe half work. Half of the work is done, butthe stone is still missing the crown.

The art of diamond polishingDiamond polishing is not an easy profession. The first requirement is what the experts call a“light hand”. Within the first few weeks itself, we get to know which of our training candidateshas a light hand and which of them has a heavy hand.A light hand implies fine motor skills together with a certain sensibility.However, physical requirements such as skills and sharp sight are by far not the only things thatmake a good polisher. Of the 11 or 12 candidates, who fulfil the conditions of admission andactually start working with us, only one stays back by the end of six months. A good polisherrequires for e.g. certain ability for good geometrical judgement. When cutting a facet, he/shemust be able to recognise, whether an angle is correct or whether it is too flat or too steep. Whenthe target is achieved while cutting the facet of a diamond, i.e. when it is large enough, this targetmust be point-shaped. After reaching its target, if a facet runs into the neighbouring facets anddoes not look pointed but like a line, it is mercilessly corrected when we give it the perfect cut.And this often means that the entire crown or pavilion must be cut again.

This is because with every correction, the neighbouring facets become very small and thesemust also be corrected again. The polisher thus needs a sense of geometry or at least an eyethat immediately tells if an angle is too big or too small. And this, often on a surface of lessthan a fiftieth of a square millimetre! When we started the polishing process 25 years ago, ourcandidates were asked questions such as the following in their interviews: At how many pointsdoes a sphere touch a cube that surrounds the sphere? With the answers that the candidatesgave, one could gauge whether a polisher has this sense of geometry or not. We only acceptapplications of those candidates who have completed at least ten years of schooling, which is nota common phenomenon in India. Cutting diamonds with the kind of precision that we demand alsotakes strong character traits. To get the better of a diamond, the hardest material known, requiresfighting spirit and willpower. If one does not put in enough efforts and dedication in diamondcutting, he/she will have such a bad output in terms of the number of pieces he/she produces thathis/her work will not be worth it. The polisher needs stamina and perseverance. He/she must beable to put in absolute concentration for hours at a stretch and must be in a position, to not letinternal stress bother him/her throughout the day.

Our polishers must develop a sense for precision and perfection in a very short period of time,which would be extraordinary in Europe. In India, all of this exists notwithstanding the environmentand the different backgrounds of people.Indian culture distinguishes itself through its expanse and tolerance.Tolerance against all the negatives as well: against poverty, pollution and chaos. This is actuallywhere we expect the exact opposite; just like we expect the opposite when it comes to the typicalIndian approach of taking everything “easy”, the attitude that nothing is really important, and a fewmore such peculiarities of the Indian mentality. Our polishers must also be flexible enough to gothrough a complete character make-over. And that is not easy. Diamond polishing with precisionis hard work – a character training, which cannot be escaped.

A diamond polisher must also havea balanced mind, because withoutequanimity and inner peace, he/shewill make mistakes. The smallestcarelessness can mean the loss of anentire stone. If the diamond is set ata wrong angle and at a wrong speed,it can go into the iron grinding diskand break into many small pieces.Work in aditi diamonds starts at 6a.m. Hot milk or tea is served aftertwo hours and starting from 9.30a.m., individual departments havelunch one by one in our two open-aircanteens. When there is no strainand the typical Indian joie de vivre is seen enjoying a break, one usually sees only laughing facesaround.

The relations between the workforce and the management are very good in general. The culturaldifferences between the German and the Indian mentality have been bridged to a great extentnow. The people have come to know each other and a synthesis of the two worlds has beenfound. In the 29 years of the company there were strikes only a couple of times – and even thesestrikes were hardly related to wages or working conditions. We experienced the first strike 22years ago, when for the first time, a woman in the workforce was earning more than most of themen. She was simply better than her colleagues and produced more stones. Her earnings weretherefore higher. In response to that, the male workforce refused to accept their pay. A womanearning the same amount of money for the same work as men was unheard of in the Indiaof 1987. The second, more serious problem was when we appointed a woman as the JuniorSupervisor. Male workers under the supervision of a woman, was already somewhat a risk inthose times. In fact, the Manager and the Senior Supervisors even received anonymous lettersfrom the workforce threatening them with deadly consequences.Equally risky was the complete disregard of the caste-system followed by the workers. Eventoday, the prevalence of caste system is so strong that, for e.g. in a vegetable market, everyIndian buys vegetables and fruits only from someone belonging to his/her caste; even if thatmeans buying things at a higher rate or lower quality than that offered by the neighbouring vendor.Our employees today would simply laugh listening to all these starting troubles. People haveadopted the western mentality in a positive way, as they deem fit.However, a big cultural problem still persists as it did 25 years back: the non-separation of maleand female workers. Till date, marriages in India are almost exclusively arranged by the parents.The so-called “love-marriages” are rare. Since in aditi diamonds, men and women work togetherwithout being segregated, we automatically see a lot of friendships taking shape, which then oftenend in a “love-marriage”. This often lands the persons concerned in serious problems with thefamily, especially if the two are from different castes and strata of society. Surprisingly, the divorcerate for love-marriages is still extremely high.The rendezvous of the Indian mentality with the European mentality in our polishing plant is achallenge for both sides. And it is not easy for either side. In the end however, the result is astructure, which is extraordinarily stable and productive and perhaps superior to both systems ofthought.

Such deals are always difficult. Big customers not only try to control the quality and the quantity inexactly defined volumes, but often also the type of cut. For example, in USA, there is a demandfor brilliants with very fine table facets and high crowns, or the so-called ideal cut. Tension ringmanufacturers want facetted girdles; wedding ring manufacturers prefer flat brilliants and watchmanufacturers determine exact tolerances for the crown angles.The biggest problem is the calibration. If a jewellery manufacturer orders 5000 brilliants of 2.9 mmdiameter in top Wesselton VS, it is barely feasible. The rough diamonds cannot be pre-selectedsuch that the size of the polished brilliants is pre-determined. Similarly, quality cannot be predeterminedeither. In both cases, one can only estimate what the result after polishing would be.To obtain 5000 stones of 2.9 mm in TW-VS, we would have to produce approximately the samequantity in one lower colour-level and one higher colour-level. Similarly, in one lower clarity-leveland one higher clarity-level, giving us 9 qualities (three colour levels and three clarity levels). Thewhole is then multiplied once again with the factor 3 or 4 because of the varying sizes. Finally,one would have to produce at least 30- to 40-times the quantity of stones to fulfil such a specificorder. If then a certain type of cut is also desired, then the order is simply not feasible: Who willthen buy the remaining 30-times quantity of stones in a specific cut?

Big jewellery manufacturers are thus forced to buy from wholesalers, who play their part and puteverything together by buying up all the required things from different polishing plants. In fact,two dealer-stages are often involved: first one is when the brokers at the stock market buy thebrilliants in large quantities from polishing plants or get them on commission, followed by thewholesalers. They buy exactly what they need and can thus fulfil selective demands of jewellerymanufacturers. If a big jewellery manufacturer wants to get round both these stages and getsome price advantage that would be offered only on buying directly from a polishing plant, thenhe has to make some compromises and rearrange his production palette such that he fans out hisdiamond purchase with respect to the quality and size. Negotiations pertaining to what is feasibleand what is not, and most importantly at what price, often bring both partners to a point wherethey run out of options.

The German specialised trade is unfortunately almost no longer a buyer of our brilliants. We sellless than 10% to the German market. A high-quality cut seldom finds any takers in Germany.The goldsmiths and jewellers there generally prefer an average to bad cut, which costs them afew euros cheaper than a perfectly fabricated product. It is sad, because the difference betweenthe effect of a well-made brilliant and a badly-cut stone is bigger than the difference between areal diamond and a zircon. Even a perfectly-cut Wesselton P1 brilliant reflects more light than abadly-cut flawless River, although the latter costs thrice as much. The saving mentality of Germanindividual dealers, who compare all price lists and buy from the cheapest wholesaler, is eventuallybetraying them. It would be better would be if they bought stones of one clarity and colour-levellower, but with the perfect cut.

The phenomenon of burnt stones thus affects our polishing plant less than those polishing plantsthat do not process any sawed raw materials. Despite this fact, we always rinse our diamonds inliquid borax between two stages of the work flow. The boric acid surrounds the diamonds witha protective layer that does not let any oxygen through. The stone can thus no longer burn. Thismethod is hardly ever used by any polishing plant, almost never in the other Indian or Chinesecompanies, who have developed their polishing plants to accommodate the cheapest possibleproduction methods. And this is how most of the brilliants produced by Indian and Chinesecompanies are more or less seriously burnt. An inexperienced layman does not recognise thewafer-thin milky film on the surface of the diamond. This graphitised coat, however, robs the stoneof 10% to 30% of its light. Owing to the fact that we process only sawed raw materials with a clearcutting structure, and the fact that we protect our stones from any contact with air using liquidboric acid during the polishing process, burnt stones are almost never a problem for us.b) Grinding groovesIf any grooves occur while polishing the brilliant, then the reason could either be that the grindingdisks have not been regularly and optimally serviced, or that cheap raw material with manyjunctions and structural changes is being cut. It is so hard that it cannot be polished properly.In our polishing plant, we have our own mechanical department, in which the grinding disks areserviced regularly. Every polisher gets a newly sharpened disk every week. The servicing helpsget rid of all grooves, the disk is again charged with diamant boart, the pointed bearing points ofthe disk axis are sharpened, re-centred and the disk is balanced again so that it does not vibratewhile cutting.Cheap-polishing plants – and certainly thousands of small family businesses, which do theirdiamond cutting in the backyard or in the basement in India and China – cannot afford suchluxury. The grinding disks are not sharpened by machine, but manually. If they cannot be servicedmanually, they are sometimes brought to far-away disk service-centres and serviced there.

The result is that most of the brilliants from cheap production plants are full of fine to mediumgrinding grooves. This is a disadvantage for the optical characteristics of the brilliant that is mostlyunder estimated. This is not about whether the end buyer would be able to see the grooves.He will not be able to and the table of the stone is usually anyway better polished than the otherfacets. The disadvantage is that almost all the light that falls on a groove in the stone is cut offfrom the natural optical path in the diamond and it either goes out or is sent on a trip within thestone through an unplanned total-reflection.A facet with many grinding grooves shatters up to 20% of the incident light. Normally, the lightpasses through two facets of a brilliant and is totallyreflected twice.If all four facets had grooves, then less than half ofthis incident light remains, till the time it leaves thestone in the direction of the observer again. Even ifthe brilliant has good colour and clarity, it yields a farmilder effect in comparison to a perfectly cut stone.

c) Wrong proportions of the stoneOf the many superlative qualities that diamond possesses as a material, the high optical densityis arguably the most important one. Diamond is the material with the highest optical density andthus the highest refractive index (n = 2.42). A diamond owes its great significance as a gemstoneto its high refractive index. The sparkling of a gemstone largely depends on what percent of theincident light is reflected based on the phenomenon of total reflection, or how much light is lostthrough partial reflection and absorption on the reflective surface or by escaping from the stoneon to the back wall. This is where the reputation of a diamond as the king of all gemstonesbecomes evident: it is the only natural material (and only in the cut form of a brilliant), thatmanages to reflect 100% of the perpendicular incident light on the stone based on total reflection.No other natural gemstone can be cut to do this. This is because even in case of a zircon, theoptical density of which is the closest to that of a diamond’s but slightly lesser, there is no facetconstellation, in which the stone reflects a 100% of the perpendicular incident light.A ray of light is totally reflected without any loss of light, if it falls on the interface of an opticallythicker medium (diamond) to an optically thinner medium (air), if it is at an angle to the interface,which is smaller than the total reflection angle of the optical medium. This angle is 65 degreesand 34 minutes in case of diamonds. So, every ray of light that falls on the facet from the insideat an angle that is smaller than 65 degrees and 34 minutes istotally reflected. Compared to that: the total reflection angleof quartz is 49 degrees. The comparison between a diamond,zircon and quartz shows the problems of total reflection.Let us take a ray of light which falls perpendicular to the tableon an outer facet of the crown near the girdle:The light ray entering the diamondvia one of the crown-facets, is beingdiffracted, since it enters through thesurface at an angle. When hitting theback wall of the diamond the ray hasan angle to the pavilion facet which issmaller than 65 degrees and thereforeis reflected totally. It is being thrownonto the opposite pavilion facet and isreflected again totally, since again it hitsat an angle smaller than 65 degrees. Itthen hits the table-facet from inside thediamond at an angle of 90 degrees andleaves the stone.At hitting a zircon, the light ray isdiffracted less than with the diamond,because of the smaller optical densityof the zircon. Therefore after a doubletotal reflection it does not reach thetable-facet from inside the zircon, butarrives at a crown-facet. Here howeverthe lightray is hitting a third time at anangle below the total reflection angle,and is reflected a third time totally. Theray therefore cannot leave the stone atthe crown and instead, invisible for thespectator, at the pavilion.With the quartz the problem of the thirdtotal reflection does not arise at all. Afterthe first total reflection, the light rayarrives at the opposite pavilion facet atan angle bigger than 49 degrees. Hencethe ray is leaving already after the firstreflection through the pavilion and is lostfor the spectator’s eye.

as is clear from the comparison, a certain angle is required for the diamond to sparkle in its fullbrilliance. If the ratio of the crown to the pavilion changes in a brilliant, if the angle of the crownfacets to the table facets change, or if the angle of the pavilion is flatter or steeper, then theperfect system of light-guiding no longer works together and the stone either loses light throughthe pavilion or scatters the reflected light too strongly in the crown. In any case, the stone losesthe maximum effect. In case of the usual, commercially cut small brilliants, this angle often starklydeviates from the ideal measures. The proportions, particularly in case of all brilliants that are cutout of raw material that cannot be sawed, vary from the ideal proportions to a great extent. If onewere to cut brilliants of perfect proportions from the so-called makables, the loss of weight wouldbe 10% to 15% more than for brilliants with bad proportions. Usually, brilliants made of makablesor cleavages (raw stones that are cleaved) have very high crowns, excessively thick girdles andthe ratios of the crown to the pavilion are not correct. In our polishing plant, meticulous attentionis paid to ensure that the proportions of all brilliants correspond to the ideal measures. We gladlyaccept a loss of weight of a couple of percent more, but we certainly prefer to produce perfectproducts.d) Excessively thick girdlesThe finer the girdle of a brilliant, the better its optical properties. A bruted girdle swallows most ofthe light that falls on the girdle from inside. A facetted girdle usually directs it outwards. In anycase, the observer cannot see the light. The thicker the girdle, the larger the amount of light lost.Naturally, the girdle should not be so razor-sharp that it breaks while setting the stone. For stonesof more than 0.50 ct, the girdle thickness must not be more than 3% of the stone diameter. In caseof small brilliants and melees (brilliants of sizes from 0.07– 0.15 ct) you can decide the thicknessof a girdle by comparing the length of the outer girdle facet with the thickness of the girdle.According to that, the girdle should be around 1/5 the length of the girdle facet; in case of biggerstones it should be only 1/7 or less.e) The direction of the crown facets to the pavilion facetsIn case of a brilliant, there are mainly three criteria for the optical effect that sets it apart from theother gemstones:1) The total quantity of the light that it reflects;2) The sparkle in the stone;3) The dispersion of the stone, i.e. the fanning out of the white colour in the primary coloursof a rainbowThe total amount of light that the brilliant reflects mainly depends on the right proportions of thestone. The same applies for dispersion. The sparkling of the stone, however, also depends on thecorrect arrangement of the individual facets with respect to each other.The “fire” of a brilliant, i.e. the individual light flashes, which are reflected by the diamond from theincident light, is most importantly dependent on whether the arrangement of the individual facetswith respect to each other has the ideal proportions. The pavilion of the stone has 24 facets.The crown has 32 facets plus the table. An incident ray of light is first divided into 24 smaller lightrays by the pavilion, which then – ideally – emerge from top again and go approximately in thesame direction from which they came.However, these 24 light rays must pass through the table or the crown facet while emerging out.These rays are deviated once again in the crown facets, since these facets are at an angle tothe light rays. Since the crown facets are arranged in three angles, the 24 light rays are dividedin three smaller rays each. There are thus 72 light rays that come out – but only in an ideal casescenario, and only if the pavilion facets are exactly under the crown facets.

If the facets of the crown are not exactly on top of the pavilion facets, then each of these 72 lightrays is again divided into two or more light rays. This gives us more than 140 emerging light rays.This makes the light rays so small that they can no longer be considered individual light flashes.Then although the brilliant lights up brightly, it is rather diffused light without any real fire. To avoidthis, the eight cut was used for smaller diamonds earlier.Here, we have only eight facets on the pavilion and eight facets on the crown of the stone. Theincident light ray is thus only divided in 8 emerging light rays. In case of diamond-studded watchdials,luxury-watch manufacturers still use the eight cut diamonds for this precise reason.Verdict: if the crown facets are not directed towards the pavilion facets, then the brilliant loses itsfire to a great extent even though all the light that it reflects is retained. This effect is seen mainlyin small brilliants. In case of big stones, the fire remains intact, since despite 140 light rays, everyindividual one can still be perceived as a light flash.f) Frayed girdlesThe phenomenon of frayed girdles is a typical consequence of a bad tool. When the grindingmachines are not balanced properly and are shaky, or if the grinder is too hard on the roughdiamonds with the friction stick, the diamonds to be bruted receive very apparent impacts. Thisresults in the diamond getting damaged around the girdle and sustains fine hair-line cracks fromthe girdle towards the inside. The consequence is considerable loss of light, because a frayedgirdle swallows a part of the light falling on the girdle facets. Regularly checking the machinesand the operation of the friction stick are thus a standard in our polishing plant.g) Varying angles in brilliants of the same lotEven when the angle or the proportions of the individual brilliants are within a range that is nottoo bad, it is still very important that these are always the same for individual stones of the samelot. If within a specific lot of brilliants, the angle for every stone is different, then the appearanceis very uneven in a flat piece of jewellery that is studded with these diamonds. The watch industryin particular must take care of this. Even in case of brilliants that have a diameter of just onemillimetre, a variation in the crown angle of just one degree also plays an important role. Thefacets of the crown are situated only a couple of thousandth of a millimetre apart, and even thenthe light rays are directed in a different direction because of that. Only if the crown angle of allbrilliants is within a tolerance limit of half a degree, a studded dial has a uniform look.We are one of the few polishing plants that can adhere to such a small tolerance limit and thereforesell a good part of our small brilliants to Swiss wholesalers, who supply to the watch industry.

The crownThe farther one progresses with the cutting of a brilliant, the more difficult it becomes to maintainthe cut within the tolerances for a 100% perfect result. This is because the polisher of a certainwork process receives instructions from each of his predecessors, which he/she must follow. Thisis not the case when it comes to the usual commercial cutting. Almost nothing matters there.However, one must adhere to many limiting values for an absolutely perfect cut. A commercialpolisher can cheat with many variables. He/she can leave the girdle thicker or thinner. He/she cancut the crown higher or deeper. He/she can make the table bigger or smaller, the angle of thecrown can be steeper or flatter etc. The polisher yearning for a perfect cut can vary these factorsonly within very very small limits. In addition, he/she must also direct the facets of the crown inhis division towards the pavilion facets. This is often completely disregarded in commercial smallbrilliant cutting.While the pavilion polisher only concentrates on cutting facets assigned to him/her perfectly,the polisher in charge of the crown must think thoroughly and divide his/her facets between thealready cut table and the already completed pavilion.The polisher thus starts placing the first facets of the crown such that later the girdle facets, i.e.the lower-most crown facets are exactly opposite to the pavilion facets. And then it is corrected tillit is perfect. With the click division, the polisher can roughly mark the position of a facet, but thefine-tuning is done manually.

The continuous checkingwith the magnifying glassis good training for the eye.The musculature, whichcontracts and relaxes thelens, is continuously inaction. The slackeningof this musculature,which leads to short- orfarsightedness with age,is thus out of question. Inour polishing plant, not asingle polisher thus needsto wear glasses even afterworking for 20 years. Ourex-master Phillippo, aSwiss national, who trainedour first polishers, still hasperfect eyesight even at theage of 80.

Between the individual work processes, the stones always come back to the checking rooms.Each and every stone is checked over and over again by the Senior Supervisor, i.e. the Head ofDepartment. If a cutting process is carried out carelessly, which might cause the eventual cuttingresult to be less than perfect, then the stone either goes back to the polisher or perhaps must alsobe completely reworked from step one.Checking is done between the following workprocesses:• Sawing• Checking• Possible modelling and checking• Bruting• Checking• Possible re-bruting and checking• Table• Checking• Pavilion• Checking• Crown• Checking• Star facets• Checking• Boiling• GradingThus, in our polishing plant there is a quality control check at least six times during the cuttingprocess. In all, 10% to 15% of the stones are reworked in one or the other way. Even stones thatare barely a millimetre in size are cut perfectly in our plant.

The star facetsThe last step while cutting is the 8 table facets, the stars. The absolute uniformity of the facetsand their exact size with respect to the stone literally give the stone its “final touch”. If this stepgoes wrong, then the impression of the whole stone is ruined.If the stars are cut even marginally bigger than they are supposed to be, the table becomes toosmall and the table edges appear concave. If the stars are even slightly smaller than required,the table will be too big and the table edges will appear convex. It is only when the 8 star facetshave the exact size required that the table edges are straight. The table then has 60% of the girdlediameter and the crown of the brilliant has the right proportions.

A good star facet polisher can produce more than 100 brilliants every day. The absolute toppolishers,who have been working with us for 10 to 15 years, can, in fact, manage up to 150brilliants per day. This means up to 1200 facets with absolute precision!! This means that with aworking day of 8 hours these polishers need only 24 seconds for one facet! In this time, he/shemust set the facet on the grinding disk at the right angle and start up the facet. Then he/she mustcorrect the angle of the dop such that the facet meets the girdle facets at the right moment andmeets the table at the exact same time as well. In this process, the size of the star facet mustbe perfect, once it is done. Furthermore, he/she must correct the angle of the dop such that thestar facet inclines neither towards its right nor towards its left crown facet. The angle must thusbe corrected in two directions, this facet must also be the exact same size as the other 7 facetsand the eventual size must be 60% of the table size. And all of that in only 24 seconds!! One canimagine that this can be achieved only with a hundred percent concentration and an enormousamount of dedication. Naturally, a routine and long-standing experience is essential to attain thislevel of perfection and speed.Once the brilliant has been “crowned”, i.e. whenthe crown is completed, it goes to the boilingdepartment. Here, it is boiled in acid and thencleansed once again with hydrochloric acid andultrasound waves. The remaining carbonised oiland grinding paste is thus removed and the stoneis ready for grading.

When a so-called lot (a gemstone package with a specific number of diamonds) is through withthe cutting process, it is boiled, weighed, counted once again and it then goes to the grading-roomfor grading. In our plant, grading is done only by women. In our experience, women are moreconsistent graders than men.Depending on the grader’s state of mind, the grading is sometimes strict and sometimes notas strict. A diamond grader must obviously try to keep these mood swings at a minimum whenevaluating. The stones are first sieved. Small brilliants are not classified and sold as per theweight, but as per the sieve size.Thus, the following categories are customary ininternational trade:Sieve size- 6½ brilliants of 0.003 to 0.02 ct+ 6½ - 11 brilliants of 0.025 to 0.07 ct+ 11 - 14 brilliants of 0.075 to 0.135 ctWeight categories are used to classify stones ofsieve sizes larger than 14.After the sieving, the stones are first graded asper the colour and then as per the clarity.

In international trade, the colour of a diamond is stated using letters. At a national level however,depending on the selling country, use of all kinds of terms is possible.The Scandinavian nomenclature is used most commonly in Germany: River, Top Wesselton,Wesselton, Topcrystal, etc. Internationally, the best colour is D (River D), followed by E (RiverE), then F (Top Wesselton +), G (Top Wesselton), H (Wesselton) and so on. The letter seriescontinues up to Z, which represents a rather yellow colour. Yellower than Z would again be moreexpensive and would fall under the fancy yellow category.

There is a problem with German names, since these are not 100% in sync with the Scandinaviannomenclature. The term leicht getöntes weiß (slightly tinted white) is not exactly the same asTopcrystal when translated into letters. The DPL Institute (Diamant Prüflabor GmbH (DiamondTesting Laboratory)) uses the term, “leicht getöntes weiß” for the colour specified under Wesselton.In DPL, this includes the letters “I” and “J”. The term top crystal is based only on the letter I; theletter J falls under crystal.The grading as per clarity is far more expensive than colour grading. Here, we classify the stonesin 7 clarity groups.The exact definition of the terms is as follows:fl (flawless) or if (internally flawless): if an average skilled expert cannot ascertain any blemishesunder 10x magnification, i.e. when the stone is free of any inclusions.vvs (very very small inclusions): when an average skilled expert finds inclusions under 10xmagnification, which are extremely difficult to see.vs (very small inclusions): when an average skilled expert finds inclusions under 10xmagnification, which are difficult to see.si (small inclusions): when an average skilled expert finds inclusions under 10x magnification,which are easy to see, but are not visible to the naked eye through the crown and which, moreover,do not affect the brilliance of the stone.p1 (pique 1) or i1 (inclusions 1): when an average skilled expert immediately finds severalinclusions under 10x magnification, or when inclusions are visible to the naked eye on seeingthrough the crown, but are very difficult to find. These inclusions must not affect the brilliance ofthe stone.p2 (pique 2) or i2 (inclusions 2): inclusions, which are easily visible to the naked eye throughthe crown and which reduce the brilliance of the stone to a small extent.p3 (pique 3) or i3 (inclusions 3): large or numerous inclusions, which are easily visible onseeing the crown or are many in number. The inclusions considerably reduce the brilliance.There is a problem with the term flawless with respect to evaluation by different institutes. InUSA, this concept is sub-divided into flawless and internally flawless. This is not the case inEurope: Flawless (Fl) means that the stone has neither inclusions nor any external marks suchas damages, rough spots, grinding grooves, etc. The term IF (internally flawless) means that thestone is internally flawless; however, it can have external signs such as twin lines etc. In Europe,both these terms together are recognised as one.In many cases, a stone that exhibits external signs would no longer get an IF or Fl grading inGermany or Belgium. While demarcating between SI and P1 for bigger stones, the definitioncannot be applied so strictly. Right from a size starting from two-carats, an SI2 can often berecognised with the naked eye. In case of bigger stones, finding flaws becomes even easier.For stones bigger than three carats, an SI1 can often be identified with the naked eye. Despitethe definition of clarity grading that is based on the 10x magnification and despite the fact thatthe specialized trade all over the world exclusively uses the 10x magnification, our graders gradeonly under 20x magnification. Thus the grading for VVS and VS categories is more precise andsomewhat stricter in general.

CertificatesThere are many institutes that certify the quality of diamonds. However, only four institutes haveinternational recognition. In case of stones of less than one carat, the best options are GIA, HRD,DPL or IGI. For stones of more than one carat, we recommend only GIA, HRD and DPL. In ourexperience, all other institutes often seriously differ from the high standard of these institutes asfar as the strictness of the grading criteria is concerned and are therefore not recommended.Even in international trade, it is only these four institutes that are actually recognised. There arehowever a few other institutes that are used by department stores and low-cost suppliers. Withcertificates from such institutes, one can get stones in Antwerp for 60% or even 50% of the price,because on a closer look, the evaluations simply do not match up to the standard.

In a detailed comparison (in case of stones of more than 1 ct), it is often difficult to say which of theinstitutes is the strictest. For stones of two to three carats, DPL is often stricter in evaluating theclarity grading than GIA. DPL is also often stricter than HRD as regards the colour grading betweenK and M. GIA is oftentimes slightly stricter than HRD in grading the higher colour categories (D– E – F). In general, GIA, HRD and DPL are recommended without having to think twice. Forstones of less than a carat, there is not much difference in the grading done by IGI and the otherthree institutes. Since IGI provides the certificates within a day and HRD often needs two to sixweeks to provide one; many IGI certificates are used for stones that are less than a carat. It isabsolutely safe. For stones that are more than 1 ct, however, we usually turn only to DPL, HRDor GIA. From a long-term point of view, it pays off to have certifications only from the recognisedinstitutes. However, one must point out the differences to their customers, since stones with a“fraud certificate” are a common phenomenon in the trade and obviously seem far cheaper oncomparing the price.

Explanation of some terms:Fluorescence: Fluorescence signifies the lighting up of a stone under UV light. The differentcategories of nil or none; slight or faint; medium and strong (sometimes strong blue) state theintensity of this lighting. Earlier, a strong fluorescence was considered a positive quality. This iswhere the term blue-white for the best colour comes from. It stands for a white stone that hasa blue fluorescence. Nowadays, a strong fluorescence is considered devaluating. The reasonis that stones with stronger fluorescence often give a somewhat milky impression. Sometimes,the stone is absolutely clear without any trace of milky impression. In such a case, a strongfluorescence would in fact be a positive characteristic for the stone, because the stone wouldthen be more “radiant” and the colour mostly brighter. Only if a stone is actually somewhat milkyshould the fluorescence be considered as a negative criterion.Minor graining or graining: This represents a change in structure of the stone, which, on beingclosely examined under the magnifying glass, looks as if the stone had something like “streaks”.This term is usually used only for flawless stones and decreases the value by up to 10% –depending on how strong the graining is. There is a distinction between minor graining, grainingand graining is present.Negligible external characteristics: This term is refers to negligible external characteristics: Forexample, a rough spot that was not completely cut is still seen on the girdle of a stone. The term“negligible external characteristics” is used only for flawless stones and hardly plays any role inthe price evaluation. It affects the value of only best quality stones (River D – flawless). Here, thecustomer wishes to have the best of the best and then often does not accept any deviation fromthe standard, irrespective of whether it affects the overall effect of the stone or not.

Internal control systemAround one million diamond polishers work in Bombay (now Mumbai) and Surat, the areas thatform the crux of the diamond cutting industry in India. Theft of stones from polishing plants isvery rare, since the stones are obviously counted before being given to the polisher. However,exchange of stones is something the industry is struggling to fight off. There is mafia, whichcontrols the exchange of stones in factories. They have special skilled people, who are trained tocontact polishers and talk them into being a part of a lucrative deal. The polisher then gets exactlythose stones, which correspond to his/her work process, the only difference being that these areslightly smaller and some quality levels lower. Every polisher who is recruited is looked after byan agent of this mafia and thus almost every polishing plant is milked by this mafia. The polishingplants then again often buy the best quality diamonds from the mafia, although they know thatthese stones possibly originate from their own factory.Thank god, this cannot happen in our polishing plant in Pondicherry! We are in the exact oppositecorner of India. Not on the west-coast, like Bombay, and not in the North, but on the east-coast andto the far south. We are the only polishing plant far and wide. That is already a huge advantage.In addition, our six-fold control system is perfect and helps us ensure flawless monitoring. Eachand every polisher receives his/her diamonds in small portions of up to 30 stones.

These are counted, weighed and checked after every work step. An exact account is maintainedfor the loss of weight. When a particular polisher’s stones seem to lose more weight on anaverage than those of his/her colleagues, then he/she is immediately pinned up in front of us andwe keep a close eye on where he/she is going wrong. Besides, our stones are graded exactly asper their qualities, before they are given for cutting and polishing. Our Senior Supervisors wouldalso be able to tell immediately if a part of the cutting has not been done in our plant. The loss thatan owner of a polishing plant incurs in Bombay because of this exchange of stones is estimated tobe 3% to 15% of his/her earnings. Despite that, the production costs of brilliants in Bombay andSurat are almost only half as much as in our polishing plant.If we were to let our stones be cut and polished in Surat, we would also have it much cheaper. Thecosts there are much lower than in our plant. The reasons behind this are lower wages, lack ofsocial security, cheaper equipment, almost no maintenance costs for the qualitatively ill-workingmachines, cheaper material like press-pots, etc. Most importantly however, we have much moreloss of weight in our stones with perfect proportions.If we were to let the cutting take place elsewhere else, we would also have the same productas all others. A price advantage is not our effective weapon in this daily fight for existence. It isquality. We are proud of the fact that in the last 25 years, we have cut and polished more than fivemillion brilliants, which are rarely surpassed by any another in quality. 5 million brilliants sparkleday after day somewhere in the world, with a brilliance that is slightly different than the usual.