Diamond under a Polariscope
|Diamonds can be split in several angles. This cleavage is dependent on the structure of the crystal lattice. While cutting a precious stone, one must consider the cleavage, because even a little excess pressure on a wrong point can crack a diamond. Even exposure to excessive heat, for e.g. with laser, can create greater inner tension on certain points leading to the stone breaking. With a polariscope one can see the optical properties, the “multi-colours” of a diamond (“pleochroism”). The reason for this effect is the uneven absorption of light depending on the direction of its dispersion. If one observes a diamond through a polariscope, one can see the tension over the different reflecting colours! It allows for the assessment of the correct starting point with the lasers. For if one cuts the diamond at the point of highest stress, there is a danger that it will shatter.|
Preparation for the laser
Laser procedure. One even sees
the laser point on the diamond.
|For the laser procedure the
stone is secured to a head by means of a special gypsum and limestone
mixture. As soon as the mixture has hardened, the head is attached onto
the laser machine. Diamonds are fundamentally suited for laser
The diamonds are cut in accordance with the markings of the planning department through this process. As a rule, the inclusions are removed by laser or later while cutting and polishing.
In this process, the diamond directly vaporizes through the absorbed laser energy, without passing through the liquid state (sublimation), the carbon is converted into CO2 and burnt residue-free.
Mr. Sanjay Bhalla of Sanghvi Exports International explained to me while passing through the different departments that at the moment there was full employment in Surat and that the company was looking for young talent for diamond cutting.
As far as the number of employees in diamond sector in Surat is concerned, I have received varying figures, but it should be over a million, approximately 1/5 of the inhabitants of the city!
The diamond cutters “Hari Krishna Exports alone employ over 6000 employees in Surat and more than 3000 in Mumbai.
| What really constitutes a cut
diamond and how can one discern its quality? In July 2010, new rules
for the grading of diamonds came into force. They were officially
termed as the “5Cs”, whereby the "5th C" stands for
“Character”. The entity authorizing the
grading rules is the “International Diamond Council”
The “5Cs” (+1) are as follows:
1. Carat (weight)
2. Clarity (purity)
6. Confidence = trust (in the seller)
[Explanation of the "5Cs"... Open here]
1. Carat (weight, abbreviation “ct”)
The name carat is derived from the Arabic/Greek name of the carob tree or locust bean tree seed (Latin Ceratonia slilqua). In earlier times known for its uniformity in weight, it was later applied to gemstones. One carat equals 0.2 grams (= 200 mg), at the same time, it is also divided into 100 points, i.e. a diamond of 0.25 carats has 25 points. This also applies to other gemstones. Diamonds can be very small; there are some even less than 0.01 carat (0.002 grams)!
Diamonds are natural crystals; that is why often they have the so-called inclusions. These could be traces of other minerals or characteristics of growth. These inclusions can affect, depending on the size, the reflection of light, which in turn diminishes the value of the diamonds. Diamonds with very small inclusions that cannot be seen with the naked eye are good for making jewellery.
International Abbreviations = International terms; Definition
FL = Flawless; even with 10x enlargement no defects inside or outside
IF = Internally flawless; nothing to see, even with the magnifying glass
VVS 1 = Very very small inclusions; extremely difficult too see
VVS 2 = Very very small inclusions; difficult too see
VS 1 = Very small inclusions; not too difficult too see
VS 2 = Very small inclusions; not difficult too see
SI 1 = Small inclusions; relatively easy to see
SI 2 = Small inclusions; easy to see
SI 3 = Small inclusions; extremely easy to see
--- For the specialists who can see with their naked eye ---
P1 = 1st pikee; difficult to see
P2 = 2nd pikee; not too difficult to see
P3 = 3rd pikee; easy to see
It is not very well-known that diamonds are found in all rainbow colours. Some colours are extremely rare and some others are found frequently. The price of the coloured diamonds is determined by the rarity of the colours and naturally by their demand. Most popular are the clear, “white” diamonds.
The terminology for the colour grading ranges from absolute colourless (D) to yellow (Z). The highest colour grading is termed River D (Highly Fine White+). The reason for it is that prior to this classification system, there was an old, less precise system with letters A, B, C. As one wanted to stand out, the new system was started with D as the first letter. The classification is as follows:
Terminology for the Colour Grading
• Exceptional White+ (D) = Highly Fine White+ (River plus, R+)
• Exceptional White (E) = Highly Fine White (River, R)
• Rare White+ (F) = Fine White+ (Top Wesselton plus, TW+)
• Rare White (G) = Fine White (Top Wesselton, TW)
• White (H) = White (Wesselton, W)
• Slightly Tinted White (I) = Lightly tinted white+ (Top Crystal plus, TC+)
• Slightly Tinted White (J) = Lightly tinted white (Top Crystal TC)
• Tinted White (K) = Tinted White+ (Crystal plus, CR+)
• Tinted White (L) = Tinted White (Crystal, CR)
• Tinted Colour (M-N) = Tinted (from Top Cape plus to Cape, TCA+ -CA)
• Tinted Colour (O-R) = Tinted (Light Yellow, LY)
• Tinted Colour (S-Z) = Tinted (Yellow, Y)
Coloured Diamonds that are termed as “fancy diamonds” have their own valuation system. Thereby the degree of colour saturation is considered in more detail
Term => Saturation Grade
faint => weak
very light => very bright
light => bright
fancy => medium
fancy dark => dark
fancy deep => deep
fancy intense => intense
fancy vivid => lively
A diamond becomes a Brilliant only through its cut and is of exceptional brilliance. A Brilliant is only one way of how a diamond is cut from many cutting techniques, but the most popular. The natural properties of a diamond, e.g. the purity and the colour concur optimally, when the cut is perfect, because only then is the light refraction and light reflection at its best.
Information about cutting of Brilliant Diamond
The sparkle, or the “fire” referred to as the light reflection of the diamond is achieved only through a perfect cut, which justifies the symmetry of the crystalline form of a diamond. The correct angles, arrangement and proportion of its facets (surfaces), which reflect the light in specific corners, are therefore crucial. Most of the diamonds are cut in 58 facets, one can estimate the culet size through this. The culet is the lower, small surface on the point of a Brilliant. This surface prevents the cutter from splitting the diamond.
The bigger the surface of the culet, lower is the value of the Brilliant. The Brilliant is valuable when there is no culet on the lower end, only a real point. In a perfectly cut diamond, the light rays entering one facet reflect on another and are then thrown back practically unbroken from the table (upper part) of the diamond. The vertically entering light in a Brilliant will reflect completely when the corner of the facets and the ratio of the upper and lower parts correspond in ideal dimensions. Only then will the aforementioned “fire” arise in a diamond. Inferior Brilliants are not often brought into the right proportions, but are cut according to weight, so that the price does not drop too low. However, due to this, these stones lose their brilliance and “fire”. Some part of the light entering the diamond is not optimally reflected and escapes laterally.
For those who want to know exactly
By means of the percentage value of the overall amount, one can recognize how good the brilliance of the stones is. This value is obtained by dividing the total height by the diameter. Flat cuts result in the percentage value being low, for too high cuts there is a very high percentage value. The ideal percentage value for round cut diamonds lies between 59% and 62%. The “table-percentage-value” is obtained by dividing the width of the table by the diameter of the diamond. Stones with a high percentage value have a large table whereas diamonds with smaller tables have a lower table value. The ideal ratio lies between 53% and 59%.
Commonly used cut-grade classifications
• Ideal/excellent: Excellent brilliance. Extremely rare and extremely beautiful cuts.
• Very good: Superb brilliance with few and slight external characteristics. Almost all the light, which appears on the stone, is reflected. Cuts that are assessed with a “very good” are of an extraordinary value.
• Good: Good brilliance, some external characteristics. A large part of the light is reflected. “Good” cuts are clearly less expensive than “very good”.
• Quite good/medium: Somewhat less brilliance; some big external characteristics, but termed as diamonds from a “good” quality cut.
• Poor or unusual: Less brilliance; big or many external characteristics. Poorly cut diamonds are mostly too flat or high cut. That leads to a large part of the light escaping from the stone without it being reflected. This quality of cut is not handled by most of the jewellers.
Terms of a Brilliant
• Total depth
Or: The diamond grading. In July 2010 new rules came into force for the grading of diamonds. They were officially termed as “5Cs”, in which the 5th C stands for “character”. The entity for authorizing the grading rule is the “International Diamond Council” in Antwerp. “Character” of a diamond fulfills all the requirements of an extraordinary quality diamond. That is, in addition to all the categories of the “4Cs, it is also termed for its perfection and balance in its entire cut, the symmetry of proportions, and the polish as being “excellent” and harmonic - one can call it a perfect diamond. This is also termed as “Triple X Stone”.
Secretly, today, we also have the “6th C”, which means confidence. It is more to do with a feeling for the buyer than the quality of a diamond. A customer must have the confidence that all the information and price of a diamond match. This confidence in the cutter and the dealer is today supported by various certificates from the producer and independent institutions. A diamond should never be bought without a certificate.
[Explanation for the “5Cs” … Close here]
[Everything about Diamond shapes… Open here]
[Diamond shapes… Close here]
[More about diamond prices…]
In May 2015, on the Internet, a Brilliant of 1 carat, with the colour “D” and purity “if” was priced at an average of 30,000 Euros. More prices at this time (always referred to 1 ct):
Colour | International term | Price (incl. VAT)
- D, Highly Fine White+ | River+ | from: 22,528.78 Euros
- E, Highly Fine | River | from: 15,371.23 Euros
- F, Fine White+ | Top Wesselton | from: 12,611.58 Euros
- G, Fine White | Top Wesselton | from: 10,828.88 Euros
- H, White | Wesselton | from 8,952.01 Euros
“The diamond afflicted with an extremely small, hardly perceptible defect, has only one tenth or less value. The diamond, whether big or small, the more recognizable defect it has, has not more than one hundredth of the value.” This strongly stated valuation of the purity of the diamond in an ancient Indian text has till today an influence on our value design.
In the ancient times, the reason for low prices of diamonds that were not pure, lay in their little or hardly existing occult-effect on the stone. At the time, the stone was not used as jewellery. That is why the visual appeal of the stone was not crucial, nor was the preference for “flawless stone” anything to do with visual appeal. The visual difference between a flawless stone and a stone with purity level of S2 cannot be differentiated with the naked eye and yet the flawless diamond costs double or triple.
[Diamond Prices… Close here]
One of the many cutting rooms
|A cut diamond has the highest
existing refraction of light (with a coefficient of 2.42!) and a
paired with a remarkable dispersion, which is why it is traditionally
ground and polished as a gemstone. The brilliance of a diamond is
brought about by the total amount of white light that is reflected
within the diamond.
The so-called fire in a diamond, on the other hand, results from the perception of colour in the eye of the beholder when the white light while viewing disperses into its prismatic colours, caused by the cut facets of the diamond. The diamond cutter also has the task of ensuring an optimal balance between the two properties, brilliance and fire, in a diamond.
For this reason, a diamond cutter requires not only talent, but also immense experience in the job. Perfectly cut diamonds enhance the price of a diamond, irrespective of its other attributes. Thus, the diamond cutter has an important, economic responsibility for the company. A good diamond cutter balances thus the facets in size and symmetry as well as the alignment of the angles and proportions optimally.
As only when all the details add up – here, especially the ratio of the upper part to the lower part, as well as the table size in relation to the height of the upper part - is the total reflection of the light possible. As the light escapes from the table, it disperses in its prismatic colours.
This occurrence, (“dispersion”), allows the fire as well as the brilliance of the diamond to be fully displayed. If the diamonds are cut too narrow or too flat, the light will not be reflected and the brilliance and the fire will be lost.
The grinding wheels are metal discs, to which the abrasive diamond powder is applied as a thin layer in a galvanized nickel matrix. While grinding, the facets of the diamonds are laid out in precise angles. Therefore, there are varying brackets, which are attached as per the type of facet and then held at a specific angle at the grinding wheel. The girdle of the diamond is its widest part. According to its size, all other dimensions are given in percentages. The girdle should lie in one plane, not too thick, nor uneven. The optimal girdle strength is “fine middle” (mid-range thickness). In order to achieve the best possible appearance, the girdle has to be worked on in a specific step. It should be consistent and uniform, and have no major differences in strength. The strength of the girdle is determined by the cut, but through precise grinding with a special machine, the best possible rounding and form can be achieved.
[Classification of the cutting grade of the girdle… Open here]
Cutting the Girdle
“The truth is hidden in the girdle.”
The girdle of a Brilliant is its broadest part. According it its size, all other measures are given in percentage. The girdle should lie in one plane, not too thick, nor uneven. The optimal girdle strength is “fine middle” (mid-range thickness). In order to achieve the best possible good “Look” – Brilliant with a facetted girdle will appear about ½ colour grade whiter - the girdle has to be worked on in specific step. It should be uniform, and have no major differences in strength. With a thick girdle too much weight of the stone will settle on the wrong side. A girdle too thin, is also not desirable, because the Brilliant at this point is vulnerable and can break or get damaged. The strength of the girdle is determined by the cut, but through precise grinding with a special machine, the best possible rounding and form can be achieved.
Girdle (% of the total depth) => cutting grade
- Extremely thin (<1.5%) => good
- Very thin (<1.5%) => very good
- Thin (2.0%) => excellent
- Middle (2.5-4.5%) => excellent
- Lightly thick (5.0-5.5%) => excellent
- Thick (6.0-7.5%) => very good
- Very thick (8.5-10.5%) => good
- Extremely thick (>10.5%) => fair
[Classification of the Girdle… Close here]
The precise cut of the girdle is a specific work step
the diamond is fully cut, only then are the facets polished at the end.
If this polishing is not carried out according to the rules, scratches
and lines can be left behind. An excellently polished diamond will have
practically no scratches. While buying a diamond, it is recommended
that a diamond with at least a polish grade of
“good” be selected. Before a diamond is sent for
sale, all relevant parameters of quality are once again examined under
the microscope. If improvable defects are discovered then the stone is
sent back to the according department.
Only at the end is the diamond polished
diamonds cut here are sent to the wholesalers, retailers and jewelers
for sale, some of them in India and also in the USA. Important for sale
is the Certificate from the Gemological Institute of America (GIA). All
diamonds that are above 1 carat are sent to the laboratories in New
York for certification. They are examined and then they receive the
GIA-Laser-Code for diamonds, which is engraved on the girdle. This Code
is transferred on to the Certificate, which is uniquely assigned to it,
ensuring the stone is always clearly identifiable.
Sanjay Bhalla explains, “A diamond with the GIA-Lasercode is in this way provided with protection, which creates further confidence among the clients. ‘De Beers ‘Forevermark’ follows this same goal. One should never buy a (big) diamond without the internationally recognized certificate. It is necessary to be cautious even with the term “enhanced” in the certificate. Such diamonds are artificially improved and are of lesser value. All diamonds certified from the important, internationally recognized institutes are furnished with a special expertise number on the girdle, inscribed by laser, just like for example at the GIA.
[Important certificates… Open here]
All the diamonds certified from important, internationally recognized institutes are furnished with a special Laser Expertise Number on the Girdle as we will see. The Expertise Number can be seen only with a 20 times enlargement under a microscope or magnifying glass and identifies clearly the diamond and related diamond certificates. Because the Certificate Guidelines can change, a new Certificate at a later time will become necessary.
Besides the respective company’s Authenticity and Original Certificates, there are only a few independent and international gemological institutes that certify diamonds. All the relevant properties of a diamond are examined and certified. Always buy diamonds with recognized certificates. Among the most prestigious are:
• GIA (Gemological Institute of America): https://www.gia.edu/
• IGI (International Gemological Institute): http://www.igiworldwide.com/
• HRD Antwerp (Hoge Raad voor Diamant): http://www.hrdantwerp.be/
• EGL (European Gemological Laboratory): http://www.eglreports.org/
• DPL (Diamond Prüflabor GmbH): http://www.diamant-prueflabor.de/
• KP (Kimberley Process): http://www.kimberleyprocess.com/
• DTC (Diamond Trading Company "): http://www.forevermark.com/
(Certificate of Authenticity "Forevermark” of the De Beers Group, with laser engraving)
[Important certificates… Close here]
Final Inspection, under the microscope and on the weighing balance
GIA Code for the girdle (click to enlarge)
|“Confidence is good,
but Inspection better” applies to companies that work with
diamonds quite aptly. My friendly companion, Mr. Gaurav Duggal, from
Hari Krishna Exports explained to me how his company solved this
inspection problem: Every diamond that a worker is issued for
processing is registered.
If the worker leaves his work place, he must again surrender the diamond/s, whereby they are registered once more, so they always know of the whereabouts of the diamonds. I think this is a good solution because the company saves on the costly and cumbersome search for specific persons, which due to sheer volume would take too long.
The average wage of the worker in a diamond firm depends naturally on his skill, and also on the size of the diamonds, which they are processing. A diamond cutter, who cuts a diamond under 3 carats earns a monthly average wage in the range of INR 18,000 to 20,000 (5/2015 = 250 to 280 €).
Naturally, one must consider these numbers in relation to the other wages and general living expenses in Surat, which then make it a good average monthly wage. The rents are especially low, for example, as compared to in Mumbai, from where, in the last few years, a large part of the diamond business has moved to Surat. Furthermore, in the firms, at least those visited by me, there are good social benefits and generous bonuses.
The people live partly in company houses, they eat lunch free of cost in the company canteens, in the afternoon there is free “chai” (tea), there is a company temple, an attached garden for the afternoon break, and at Hari Krishna Exports, I saw a massage sofa, just like the ones you find at airports. The company owns its own school for the diamond cutters, where young workers are introduced to the responsibility of this work.
|The biggest bonuses in the whole of India were given by Hari Krishna Exports in the year 2014 at Diwali, the Indian festival of lights, an important Hindu festival lasting for many days, which perhaps one, due to its spiritual and social reference can compare to the Christian festival, Christmas. 1,200 employees of the company who had qualified for the company “Loyalty Programme” could as bonus, choose between three gifts: a Fiat Punto, a deposit payment for a 2-bedroom apartment, or gold and diamond jewellery.|
[Quotes, Thanks and Concerned Persons… Open here]
“However it is best to clearly explain your project. As you know the diamond sector is very much based on trust, and sometimes quite reluctant towards journalists. References such as from German Consul-General for instance could also help.”
Eduard van Kleunen, Consul, Consulate General of Belgium
* * *
“In regard to your request to visit diamond cutting & jewellery manufacturing unit in Surat, we will appreciate if you could meet us on Monday at 12 noon at our office. It will help us to understand your work done in this industry & take your request forward.”
Raksha Manihar, The Gem & Jewellery Export Promotion Council
* * *
“It was great to see your work on various walks of life. GJEPC will be glad to assist you in doing the story on Diamonds. Kindly intimate us in advance to organise your trip to diamond Manufacturing Unit in Surat. We will be glad to help you with all the material or data on the industry for your work.”
Dolly Choudhary, The Gem & Jewellery Export Promotion Council
* * *
Contacs and help
I warmly thank the following people:
- Ms. Chandrika Javeri, Mumbai
- Mr. Niki Mehta, Mumbai
- Mr. Sanjay Kothari, Mumbai
German Conulate General, Mumbai
- Mr. Michael Siebert, German Consul General
Belgian Consulate General, Mumbai
- Mr. Karl van den Bossche, Belgian Consul General
- Mr. Eduard van Kleunen, Belgian Consul
The Gem & Jewellery Export Promotion Council (GJEPC)
- Ms. Dolly Choudhary, Mumbai
- Ms. Raksha Manihar, Mumbai
- Ms. Jilpa Sheth, Surat
Sanghavi Exports International Pvt. Ltd.
- Mr. Chandrakant R. Sanghavi
- Mr. Sanjay Bhalla
- Mr. Jayendra Shah
- Mr. Jagadpal
- Mr. Sohel Mehta
- Mr. Rupin Vora
Hari Krishna Exports Pvt. Ltd.
- Mr. Pintu Dholakia
- Mr. Gaurav Duggal
I would also like to thank Mr. Michael Bonke from the Bonke Diamond Jewellers, from whom I received immense information on the diamond history in India. Here the link to his Homepage: http://www.michaelbonke.com/
[Quotes, Thanks and Concerned Persons… Close here]