Stones of many colours

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By 2017-12-10

By Sanuj Hathurusinghe
Ceylon Today Features

Prince Henry of Wales (more commonly known as Prince Harry)'s engagement to American actress Meghan Markle made the headlines this month, bringing to mind the engagement of his elder brother, Prince William. After the Duke of Cambridge, Price William, proposed to Kate Middleton back in 2010, the newly engaged royal couple appeared in front of the cameras to make it official. Middleton wore an eye-catching royal blue outfit but what the cameras focussed most was on the engagement ring she wore. The ring with a 12-carat oval blue sapphire belonged to the late Princess Diana and was eventually passed on to Middleton.

The style of the ring soon became the most sought after for engagement rings in England and the demand for blue sapphires in the international market too rose unexpectedly. How is all this of any importance to us? It's because of course, the world-famous blue sapphire at the heart of the iconic ring came from a mine in Sri Lanka, some 35 years ago.
Best blue sapphire producing country

"The ring unknowingly created a tremendous demand for our blue sapphires, a demand which could not even be coped with" says Director (Valuation/Gemmology) of the National Gem and Jewellery Authority (NGJA), K. L. D. Dayasagara.
Even without the spotlight being placed over us all of a sudden, Sri Lanka has been the best country in the world to produce Blue Sapphires for ever so long. Burma and Kashmir too produce Blue Sapphires but Burma; not in the quantities we do, and Kashmir; less as well due to civil conflicts in the area.

Why cut gems?
Found in Sri Lankan soil are gems which are the most precious in the world such as Sapphires, Cat's Eyes and Alexandrites and also semi-precious stones such as Garnets, Spinels, Amethysts and Citrines. A fresh-out-of-the-mine gemstone of any kind doesn't look that appealing and has no symmetry to it. What adds value to the stone is cutting it, sanding it and polishing it so that the gem is suitable to be used in jewellery.
"You cut a gemstone into a certain shape so that the light goes into the stone and gets reflected back from the face of the stone. If not properly cut, light will not get reflected but refracted. Traditionally, our cutters had the tendency to keep much of the stone's original weight as possible. But that is not accepted by the trade now. It results in a stone with a bulging bottom which cannot be put onto a piece of jewellery. Now you have to stick to internationally accepted proportions. Once you have stuck to your proportions the end product usually will be of one fourth or one third the original stone's weight. It depends on the shape of the raw stone" revealed Dayasagara.

Nonetheless, a properly cut stone has a hefty price tag on it. One carat (200 milligram) of such a gem is usually valued between Rs 5 and 10 lakhs.

Role of a Gem Designing Technician
Unlike butchery or dress cutting, facetting a gem is a delicate procedure throughout and requires 100% concentration of the technician. A Gem Designing Technician is someone who can make a raw stone a very precious one or can ruin it altogether. With a slight slip of the hand a fraction of a carat could be cut off from the stone and reshaping it will result in further cutting and the value being reduced.

One could compare gem facetting to a form of art as the end product certainly has that artistic beauty to it. While it is better for a Gem Designing Technician to have steady hands like a painter or a sculptor, Dayasagara says it is not a must. General knowledge on Gemmology though is a must. When you cut stones like sapphires, the stone has to be oriented in a certain manner to get best colour and best brilliance. 'Brilliance' is the amount of white light reflected back while 'colour' is getting maximum light out from the gem. In a gem there is a direction called the optic axis. You have to find this optic axis and orient the stone faced at right angles to the optic axis. To find the optic axis in a raw stone requires a bit of knowledge of Gemmology" revealed Dayasagara.

The technician gives the initial shape using a grinder with a special grinding wheel in which the grit size is very small. The grit size gets gradually reduced for finer grinding. Then the stone gets sanded to make it smoother before finally getting a proper polish. While grinding and sanding is done in a watery medium to prevent excessive heat generation, polishing excludes water as the process requires heat to have molecular changes on the surface for a finer finish.


Gem cutting machinery
Gem cutting has a rich history to it. In ancient times, kings had people working under them who specialized in gem facetting. These gem cutters used 'Hanaporuwa', a totally manual instrument used in grinding and sanding gemstones and another instrument called the 'polishing bench' to give the desired finish to the stone. Lapidaries back then had also made cooling glasses out of a gemstone called aquamarine for kings. Descendants of these gem cutters still live in Pilimathalawa.

Technology has come a long way since the Hanaporuwa but it is still being used to give big stones their initial shape or outline. Veteran cutters in Demuwawatha and Ratnapura use the Hanaporuwa to cut Star Sapphires and Cat's Eyes. The industry started blooming in the '70s and more sophisticated machines were introduced to facet gems. Machines built in Japan, Thailand and Switzerland were introduced to the Sri Lankan industry but only the Japanese and the Thai gem facetting machines survived. Unfortunately, the Swiss one was too sophisticated and expensive for our industry's liking.

Gem cutting techniques
According to Dayasagara, there are three main categories in gem cutting.
If a stone is highly valuable, it is cut according to its original size and shape without bothering too much about specific measurements. This is called free size cutting and is done mostly on 15 to 20 carat stones.

In calibrated cutting the length and breadth of the stone has to be accurate. This method of cutting is preferred by jewellery manufacturers as calibrated gems are desired in making jewellery. Calibrated cutting is a separate sub-industry within the industry that carries a lot of demand.

Found inside machines of expensive wristwatches are hundreds of small stones. These stones are precisely cut in order for the machine to work with acute precision. "In calibrated cutting, a tolerance of 0.01 millimetres, plus or minus is allowed. In precision cutting, there is no tolerance. All the stones should be of same weight, length and breadth. In precision cutting, what you pay for is about four times the value of the raw material" says Dayasagara.

A promising industry
Dayasagara says that the industry has a lot of potential. We are not only exporting facetted gems but fulfil orders from other countries to facet gems as well. Our gem facetting is world-famous for quality as well as affordability. "A job that costs over 1,000 dollars in USA can be done in Sri Lanka for about 30 dollars" says Dayasagara. Apart from exporting, we are in the business of buying raw stones from African countries, doing a little bit of value adding here and selling them back in the international market. This way, our own resources wouldn't run out due to over-mining and at the same time, the demand for gems would also be met.
Gem cutting requires skill rather than force. Gem mining however, demands muscle over brain and is still considered to be a risky occupation. Miners are the ones who actually risk their lives to unearth the gems we adore. The NGJA has not forgotten them either. Dayasagara says that the miners too are looked after through a newly designed pension scheme. "We saw the same kind of initiative in a different government institute. We adopted it to our industry seeing all the positives of it," says Dayasagara. The life insurance and pension scheme are designed for the welfare of not just gem miners but everyone occupied in the gem industry and their families as well.

"We intend to take our miners to other gem-mining countries like Ethiopia and Tanzania and start mining there. It basically is Sri Lanka going international. We lack about 10,000 to 15,000 Gem Designing Technicians in the industry at the moment." Dayasagara invites more individuals to get involved in the industry which promises a lot for the talented.

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