(via Economic Times) China's sizzling economy grew even faster in 2006 than previously reported, bringing it closer to overtaking Germany as the world's third-biggest, and its export-fueled foreign reserves have risen to a new high of $1.33 trillion, according to new government data.
The figures released Wednesday reflect China's stunning economic success but could fuel fears of overheating and prompt Beijing to boost interest rates or tighten regulatory controls to cool the boom. The National Bureau of Statistics raised its estimate of China's 2006 growth rate from 10.7 per cent to 11.1 per cent. It nudged up its estimate of total output to 21.1 trillion yuan ($2.705 trillion; euro 2.048 trillion), bringing China closer to overtaking Germany as the world's No. 3 economy after the United States and Japan.
The statistics agency routinely issues such revisions to economic growth rates. But the latest report could receive special attention from Chinese leaders, who are trying to rein in a boom that they worry could ignite a financial crisis.
Chinese leaders want to maintain fast growth to reduce poverty but are trying to slow investment in auto manufacturing, real estate and other areas where supply outstrips demand. They worry that runaway spending could ignite inflation or leave banks and borrowers with dangerously high debt levels.
The central bank's research bureau said last month the economy was expected to expand by 10.8 per cent this year. That was in line with projections by the World Bank and other economists, and would be China's fifth straight year of growth in excess of 10 per cent. China's trade surplus soared to a new monthly high of $26.9 billion (euro 19.8 billion) in June, the government reported Tuesday. The flood of export revenues has forced the central bank to drain billions of dollars a month from the economy through bond sales to reduce pressure for prices to rise, piling up the money in US Treasury’s and other foreign securities and helping to finance Washington's budget deficit.
The reserves, already the world's largest, rose to US$1.33 trillion (euro 965 billion) at the end of June, a 41.6 per cent increase over the same time last year, the official Xinhua News Agency said, citing the central bank. The reserves soared by $266.3 billion (euro 193 billion) in the first six months of this year, more than in all of 2006, the bank said. Beijing is creating a company to make more profitable use of the reserves through commercial investments abroad. Plans call for the company to receive an initial injection of $200 billion (euro 160 billion) in government money.
Friday, July 13, 2007
Toxic Trinkets
(via Harvard's World Health News) An investigation by Florida's Tampa Tribune finds unsafe amounts of lead in inexpensive jewelry marketed to children.
"They're an irresistible buy: cheap children's jewelry and toy trinkets, lining the shelves of some of the nation's best-known retailers. And though consumers snap up these adorable items by the millions, retailers love them even more. They cost little to make overseas and can be highly profitable. But such trinkets are exposing America's children to potentially lethal levels of lead, a cheap bonding agent. The Tampa Tribune conducted an investigation of stores and federal regulations aimed at protecting consumers from such hazardous products. It found: One in three children's trinkets bought randomly in Bay area stores last month contained a level of lead considered a serious health risk to children younger than 6. Two pieces were purchased after in-house or national recalls of the toxic products had been issued, but items remained on local store shelves. Health officials, government regulators and retailers say there's no foolproof system to keep lead-tainted products out of stores, given inconsistent and lax quality controls at overseas factories. About 9 million pieces of children's jewelry have been recalled since 2006, but an understaffed and underfunded U.S. consumer regulatory agency has failed to fine a U.S. retailer or distributor for selling jewelry containing toxic levels. Blame the flood of potential danger on an expanding global marketplace."
"They're an irresistible buy: cheap children's jewelry and toy trinkets, lining the shelves of some of the nation's best-known retailers. And though consumers snap up these adorable items by the millions, retailers love them even more. They cost little to make overseas and can be highly profitable. But such trinkets are exposing America's children to potentially lethal levels of lead, a cheap bonding agent. The Tampa Tribune conducted an investigation of stores and federal regulations aimed at protecting consumers from such hazardous products. It found: One in three children's trinkets bought randomly in Bay area stores last month contained a level of lead considered a serious health risk to children younger than 6. Two pieces were purchased after in-house or national recalls of the toxic products had been issued, but items remained on local store shelves. Health officials, government regulators and retailers say there's no foolproof system to keep lead-tainted products out of stores, given inconsistent and lax quality controls at overseas factories. About 9 million pieces of children's jewelry have been recalled since 2006, but an understaffed and underfunded U.S. consumer regulatory agency has failed to fine a U.S. retailer or distributor for selling jewelry containing toxic levels. Blame the flood of potential danger on an expanding global marketplace."
The Pleasures Of Discovery
2007: A real treat from a gemological genius. Good tips for students of gemology, lab gemologists, gem dealers, jewelers and those who love colored stones.
(via The Journal of Gemmology, Vol.XIV, No.3, July 1974) B W Anderson writes:
(being the substance of a talk given to the Gemmological Association of Great Britain at Goldsmith’s Hall on 29th October, 1973)
In the talk I gave in January I described our early struggles in the Precious Stone Laboratory from 1925 onwards, first in learning our main job of pearl testing and later in improving and extending the techniques for testing gemstones of all kinds. Tonight, in continuing the inside story of the Laboratory I am proposing to stick pretty closely to one main theme rather than risk getting lost in recalling a host of little incidents: the theme being the story of discoveries of new gem varieties and new gem minerals in which we were lucky enough to be involved to a major or minor extent.
At present time there are some 2500 separate mineral species known to science. Each year a number of new names are added, but most of them are not only very rare but quite insignificant in form. One sometimes feels rather sorry for some worthy scientist whose name is given by its discoverer as compliment to some very indifferent mineral! The small importance of most of these in indicated by the fact that in a standard textbook such as the 1971 edition of Dana’s Manual of Mineralogy only some 200 species were considered worthy of description.
But the discovery of a new gem mineral is a rare event, for it implies that the specimens found are at least large enough to be cut as stones suitable for jewelry, and usually that they are transparent and pleasingly colored. From the trade point of view the recovery of new varieties of an already known mineral may be much more important. One has only to think of demantoid (1878), kunzite (1902), and tanzanite (1967) as instances of this.
Gahnospinel
Our first investigation into stones which had not previously been described concerned certain blue spinels from Ceylon which had a normal appearance but which were found to have a refractive index, and particularly a density, which was far higher than any quoted in the literature. C J Payne and I had already noted several such anomalous stones, but the real challenge came in 1935 when T W Oliver, who was then a gemology student at Chelsea Polytechnic, showed me a blue spinel which puzzled him in having a refractive index of over 1.74 instead of customary 1.715 or 1.72 of a spinel with so pale a lavender blue. In the laboratory we found the actual figures to be 1.7432 for the refractive index (using the minimum deviation method), and the density to be 3.947, which was even more startling.
The hunt was now on: we set to work in earnest to search for comparable stones, working through parcels of Ceylon stones borrowed from the rich stock of E Hahn & Sons, who were in those happy days established in 26, Hatton Garden. We also segregated by means of Clerici solution high density blue spinels from samples of the Ceylon gem gravels. The rarity of these anomalous stones is indicated by the fact that of over 300 spinels examined, only four had densities above 3.85.
Eventually we had in our hands a graduated range of blue spinels ranging from No.1 specimen, which was a pebble polished as a prism by Mathews Lapidaries, which gave us the measured figures of 1.7469 for refractive index and 3.981 for density, down to No.22, which had the normal values of 1.7153 and 3.584 respectively.
We realized that the replacing element causing these enhanced figures had to be one known to form a ‘spinel’ on its own and one which would have no influence on the color. Our guess that this element was zinc soon proved to be correct. We prepared a graph on which we plotted the density and refractive index of pure magnesium spinel and the corresponding figures (4.625 and 1.805) for a man-made zinc spinel, known in nature as the mineral gahnite. The zinc-rich spinels of our newly discovered series found to fit satisfactorily along the line between the two points and were well away from the line leading from the plot for magnesium spinel to that for the iron spinel, hercynite. Our ‘gahnospinels’, as we christened them, varied in color from pale to dark blue, according to their content of ferrous iron, but this had very little influence on their properties. Any considerable influx of iron causes spinel to become black and opaque and fit only for mourning jewelry. Ceylonite and pleonaste are variety names which have been used for such stones, typical values for which are 3.8 for density and 1.78 for refractive index.
We also used a small grating spectrograph made for us by Bellingham and Stanley to record the emission spectrum of small samples of stones selected from our series, fusing them in a purified carbon arc for the purpose. The spectra not only showed the expected increase in the strength of the zinc emission lines in the higher density samples, but also revealed the unexpected fact that all blue spinels from Ceylon contain at least a trace of zinc.
Dr Max Hey, the highly skilled analyst in the Mineral Department of the Natural History Museum, kindly carried out a quantitative analysis of one our ‘top’ stones and found it to contain 18.21% zinc oxide, 16.78% magnesium oxide, and 1.93% ferrous oxide—to which last the color and absorption spectrum were due. We then had enough data to justify a paper on these stones, which was published in the Mineralogical Magazine—this being the Journal of the Mineralogical Society, which is the accepted vehicle for contributions to mineralogy in this country.
This whole investigation was ideal for our first serious incursion into mineralogy. In those far-off days specimens for our purpose were readily and cheaply obtainable (Ceylon, it may be remembered, was still under the British rule); we had recently acquired a Beck table spectrometer, which enabled us, with suitably cut stones, to measure refractive indices and dispersions to four decimal places, and we were able to make accurate density determinations even on small specimens by suspension in Clerici solution followed by measurement of the R.I of the solution to our places of decimals in a hollow prism and working from a graph we had prepared showing the connexion of the density and R.I of this solution. It also gave us practice in an essential part of all research work—the art of ‘consulting the literature’ to ensure that our findings had not been already written by other workers.
A brief word on this last process may be of help to beginners in this fascinating business called research. Looking round the shelves laden with scientific journals in a big science library, such as the one in Southampton Buildings off Chancery Lane, which was formerly the Patent Office Library and is now the Science Library of the British Museum (proximity to which was not the least of our blessings), one might despair of making a thorough search. But it is not so difficult as it seems. For the past few decades at least, Mineral Abstracts have existed and a rapid search through the indexes of their more recent volumes under ‘spinel’, say, will lead you to papers on the subject that interests you. Consulting the latest of these will provide you with all the necessary references up to that time: the author will have done that work for you. A knowledge of German may be helpful, but copying facilities are provided by the library, and in ten minutes you can be provided with a photocopy which you can brood over at your leisure.
Before leaving the subject of gahnospinel I might mention that the highest figures yet encountered were in blue spinel sent for a routine test in 1964. This had density 4.06 and refractive index 1.7542. It is hardly likely that even so extreme a case might be confused with sapphire, but it is not uncommon for stones containing only a small proportion of zinc to have refractive indices around the 1.728 mark—a value associated in the mind with synthetic spinel.
The Pleasure Of Discovery (continued)
(via The Journal of Gemmology, Vol.XIV, No.3, July 1974) B W Anderson writes:
(being the substance of a talk given to the Gemmological Association of Great Britain at Goldsmith’s Hall on 29th October, 1973)
In the talk I gave in January I described our early struggles in the Precious Stone Laboratory from 1925 onwards, first in learning our main job of pearl testing and later in improving and extending the techniques for testing gemstones of all kinds. Tonight, in continuing the inside story of the Laboratory I am proposing to stick pretty closely to one main theme rather than risk getting lost in recalling a host of little incidents: the theme being the story of discoveries of new gem varieties and new gem minerals in which we were lucky enough to be involved to a major or minor extent.
At present time there are some 2500 separate mineral species known to science. Each year a number of new names are added, but most of them are not only very rare but quite insignificant in form. One sometimes feels rather sorry for some worthy scientist whose name is given by its discoverer as compliment to some very indifferent mineral! The small importance of most of these in indicated by the fact that in a standard textbook such as the 1971 edition of Dana’s Manual of Mineralogy only some 200 species were considered worthy of description.
But the discovery of a new gem mineral is a rare event, for it implies that the specimens found are at least large enough to be cut as stones suitable for jewelry, and usually that they are transparent and pleasingly colored. From the trade point of view the recovery of new varieties of an already known mineral may be much more important. One has only to think of demantoid (1878), kunzite (1902), and tanzanite (1967) as instances of this.
Gahnospinel
Our first investigation into stones which had not previously been described concerned certain blue spinels from Ceylon which had a normal appearance but which were found to have a refractive index, and particularly a density, which was far higher than any quoted in the literature. C J Payne and I had already noted several such anomalous stones, but the real challenge came in 1935 when T W Oliver, who was then a gemology student at Chelsea Polytechnic, showed me a blue spinel which puzzled him in having a refractive index of over 1.74 instead of customary 1.715 or 1.72 of a spinel with so pale a lavender blue. In the laboratory we found the actual figures to be 1.7432 for the refractive index (using the minimum deviation method), and the density to be 3.947, which was even more startling.
The hunt was now on: we set to work in earnest to search for comparable stones, working through parcels of Ceylon stones borrowed from the rich stock of E Hahn & Sons, who were in those happy days established in 26, Hatton Garden. We also segregated by means of Clerici solution high density blue spinels from samples of the Ceylon gem gravels. The rarity of these anomalous stones is indicated by the fact that of over 300 spinels examined, only four had densities above 3.85.
Eventually we had in our hands a graduated range of blue spinels ranging from No.1 specimen, which was a pebble polished as a prism by Mathews Lapidaries, which gave us the measured figures of 1.7469 for refractive index and 3.981 for density, down to No.22, which had the normal values of 1.7153 and 3.584 respectively.
We realized that the replacing element causing these enhanced figures had to be one known to form a ‘spinel’ on its own and one which would have no influence on the color. Our guess that this element was zinc soon proved to be correct. We prepared a graph on which we plotted the density and refractive index of pure magnesium spinel and the corresponding figures (4.625 and 1.805) for a man-made zinc spinel, known in nature as the mineral gahnite. The zinc-rich spinels of our newly discovered series found to fit satisfactorily along the line between the two points and were well away from the line leading from the plot for magnesium spinel to that for the iron spinel, hercynite. Our ‘gahnospinels’, as we christened them, varied in color from pale to dark blue, according to their content of ferrous iron, but this had very little influence on their properties. Any considerable influx of iron causes spinel to become black and opaque and fit only for mourning jewelry. Ceylonite and pleonaste are variety names which have been used for such stones, typical values for which are 3.8 for density and 1.78 for refractive index.
We also used a small grating spectrograph made for us by Bellingham and Stanley to record the emission spectrum of small samples of stones selected from our series, fusing them in a purified carbon arc for the purpose. The spectra not only showed the expected increase in the strength of the zinc emission lines in the higher density samples, but also revealed the unexpected fact that all blue spinels from Ceylon contain at least a trace of zinc.
Dr Max Hey, the highly skilled analyst in the Mineral Department of the Natural History Museum, kindly carried out a quantitative analysis of one our ‘top’ stones and found it to contain 18.21% zinc oxide, 16.78% magnesium oxide, and 1.93% ferrous oxide—to which last the color and absorption spectrum were due. We then had enough data to justify a paper on these stones, which was published in the Mineralogical Magazine—this being the Journal of the Mineralogical Society, which is the accepted vehicle for contributions to mineralogy in this country.
This whole investigation was ideal for our first serious incursion into mineralogy. In those far-off days specimens for our purpose were readily and cheaply obtainable (Ceylon, it may be remembered, was still under the British rule); we had recently acquired a Beck table spectrometer, which enabled us, with suitably cut stones, to measure refractive indices and dispersions to four decimal places, and we were able to make accurate density determinations even on small specimens by suspension in Clerici solution followed by measurement of the R.I of the solution to our places of decimals in a hollow prism and working from a graph we had prepared showing the connexion of the density and R.I of this solution. It also gave us practice in an essential part of all research work—the art of ‘consulting the literature’ to ensure that our findings had not been already written by other workers.
A brief word on this last process may be of help to beginners in this fascinating business called research. Looking round the shelves laden with scientific journals in a big science library, such as the one in Southampton Buildings off Chancery Lane, which was formerly the Patent Office Library and is now the Science Library of the British Museum (proximity to which was not the least of our blessings), one might despair of making a thorough search. But it is not so difficult as it seems. For the past few decades at least, Mineral Abstracts have existed and a rapid search through the indexes of their more recent volumes under ‘spinel’, say, will lead you to papers on the subject that interests you. Consulting the latest of these will provide you with all the necessary references up to that time: the author will have done that work for you. A knowledge of German may be helpful, but copying facilities are provided by the library, and in ten minutes you can be provided with a photocopy which you can brood over at your leisure.
Before leaving the subject of gahnospinel I might mention that the highest figures yet encountered were in blue spinel sent for a routine test in 1964. This had density 4.06 and refractive index 1.7542. It is hardly likely that even so extreme a case might be confused with sapphire, but it is not uncommon for stones containing only a small proportion of zinc to have refractive indices around the 1.728 mark—a value associated in the mind with synthetic spinel.
The Pleasure Of Discovery (continued)
Danburite
Chemistry: Calcium boro-silicate
Crystal system: Orthorhombic; striated prisms of diamond-shaped cross section, terminated by domes; distinctive chisel-shape appearance; habits similar to topaz.
Color: Transparent; yellow and colorless; rarely pink.
Hardness: 7
Cleavage: None; Fracture: sub-conchoidal.
Specific gravity: 3.0
Refractive index: 1.63 – 1.64; Biaxial positive/negative; 0.006
Luster: Vitreous.
Dispersion: Low
Dichroism: -
Occurrence: Burma, Madagascar, Mexico, Australia.
Notes
Collector’s stone; distinguished from topaz (S.G = 3.53) by lower S.G; Apatite (D.R: 0.003) by higher D.R and Tourmaline (D.R: 0.018) by lower D.R; may show rare earth spectrum; usually faceted.
Crystal system: Orthorhombic; striated prisms of diamond-shaped cross section, terminated by domes; distinctive chisel-shape appearance; habits similar to topaz.
Color: Transparent; yellow and colorless; rarely pink.
Hardness: 7
Cleavage: None; Fracture: sub-conchoidal.
Specific gravity: 3.0
Refractive index: 1.63 – 1.64; Biaxial positive/negative; 0.006
Luster: Vitreous.
Dispersion: Low
Dichroism: -
Occurrence: Burma, Madagascar, Mexico, Australia.
Notes
Collector’s stone; distinguished from topaz (S.G = 3.53) by lower S.G; Apatite (D.R: 0.003) by higher D.R and Tourmaline (D.R: 0.018) by lower D.R; may show rare earth spectrum; usually faceted.
Thursday, July 12, 2007
The Culture Of The GIA Synthetic Certificate Debate
Chaim Even-Zohar writes about the issues discussed at the GIA Symposium in San Diego + consumer confidence issues + FTC vs. industry governing bodies + other viewpoints @ http://www.idexonline.com/portal_FullEditorial.asp?TextSearch=&KeyMatch=0&id=26152
SA's New Diamond Regulator Takes Shape
Polished Prices writes:
The South African government moved ahead this week with several key appointments to its state diamond regulatory body.
Among the appointments for the new regulator - in charge of licencing, the Kimberley Process and beneficiation - is Louis Selekane, current CEO of the South African Diamond Board, who will become chief executive.
Martin Mononela, previously chief director at the Department of Minerals and Energy, will act as general manager. According to Mononela, the boards of the State Diamond Trader as well as the regulator – each comprising of 16 civil and industry representatives – have already been appointed.
Based on the new South African Diamond legislation, 10% by value of the country’s diamond production must be made available to the State Diamond Trader. The government is currently in the process of appointing a State Trader, whose activities will be overseen but its own independent board of directors.
Licence holders applying for goods from the State Diamond Trader are required to polish and cut 80% of their supplies in South Africa. The remaining 20% is exempted from export duty, said Mononela.
“After personnel have been put in place at the trading body, the trading will begin," said Mononela, adding this could be as early as August 2007. “In terms of the law, the negotiations have been finalised with the producers,” he said.
The President is expected to promulgate the new legislation no later than August 2007.
More info @ http://www.polishedprices.com/article.shtml?ID=1000004502
The South African government moved ahead this week with several key appointments to its state diamond regulatory body.
Among the appointments for the new regulator - in charge of licencing, the Kimberley Process and beneficiation - is Louis Selekane, current CEO of the South African Diamond Board, who will become chief executive.
Martin Mononela, previously chief director at the Department of Minerals and Energy, will act as general manager. According to Mononela, the boards of the State Diamond Trader as well as the regulator – each comprising of 16 civil and industry representatives – have already been appointed.
Based on the new South African Diamond legislation, 10% by value of the country’s diamond production must be made available to the State Diamond Trader. The government is currently in the process of appointing a State Trader, whose activities will be overseen but its own independent board of directors.
Licence holders applying for goods from the State Diamond Trader are required to polish and cut 80% of their supplies in South Africa. The remaining 20% is exempted from export duty, said Mononela.
“After personnel have been put in place at the trading body, the trading will begin," said Mononela, adding this could be as early as August 2007. “In terms of the law, the negotiations have been finalised with the producers,” he said.
The President is expected to promulgate the new legislation no later than August 2007.
More info @ http://www.polishedprices.com/article.shtml?ID=1000004502
A Diamond District Far From 47th Street
Hilary Larson writes about Brugges and Antwerp + its international status as the center for diamonds and fashion + other viewpoints @ http://www.thejewishweek.com/news/newscontent.php3?artid=14252
Precious Stones Of The Future From The Laboratory
An insider (s) view + tips for students studying synthetic gemstone identification course (s).
(via The Journal of Gemmology, Vol.XVI, No.7, July 1979)
A report on M. Pierre Gilson’s talk
On the 11th October, 1978, a talk was given to members of the Association by M Pierre Gilson on ‘Precious Stones of the Future from the Laboratory’ in the Geological Museum Cinema Theatre, South Kensington. The theatre was full when the proceedings were opened and the speaker was introduced by the vice-chairman, Dr David Callaghan, FGA, who said M Gilson produced the very best that man could produce and was able to do in a relatively short time things which Nature took very much longer to achieve; his talent and the vast range of materials that he was producing were quite fantastic.
M Gilson’s talk then took the form of a running commentary no the hundred or so slides which he showed during the evening and he left few people in doubt about the progress made in the last fifty or sixty years. He reminded the audience that Verneuil was the first to make synthetic ruby and sapphire at the beginning of the century: with his relatively simple method he was able to produce a boule in one of several colors in a matter of three hours or so, and his synthetic corundum was soon used to make the jewels in watches.
In contrast, M Gilson’s company takes as long as nine months to grow synthetic emeralds. They start with a seed—synthetic material of the highest quality—and grow it as a non-stop process for nine months. A continuous supply of electricity is essential, because it is important to allow crystallization to take place at a constant temperature if good crystals are to be grown. Accordingly arrangements have been made to ensure that the company is guaranteed a supply of electricity privately in case there should be a failure in the public supply due to breakdown or perhaps a strike.
But it is not just a matter of having the right equipment and know how: experimentation also is necessary. Before success in making synthetic turquoise was achieved, thirty different phosphates had to be crystallized.
The equipment now used in the Gilson laboratories is very sophisticated and quite advanced. In order to study the size and formation of the tiny ‘beads’ which make up such gemstones as emeralds an electron microscope is used. A spectrophotometer is another essential piece of equipment, because it is important to be able to control absorption to within one part per million.
With synthetic emeralds M Gilson has found it beneficial to cut at a specific angle in relation to the seed crystal on which the new material has been grown. He used slides to explain that the main difference between synthetic and natural emerald lies in the nature of the inclusions. In the synthetic material the ‘veil’ is twisted, whereas in the natural stone it is straight. He added that Nature produced only one good emerald for every million crystals formed: in the laboratory it was essential to have a very much higher success rate. Emerald production in the Gilson laboratory takes precisely nine months, since, if you wait any longer, crystallization may have stopped. A simple—but impractical! –test to distinguish between natural and synthetic emerald was mentioned: if you heat it to one thousand degrees and it turns white when it cools, you know it is natural. He added that the hardness of emerald was affected by the extent of inclusions in a given stone.
Opal was next discussed. Opal is pure silica: it acts like a prism and the colors which can be seen are pure spectral colors. Gilson synthetic opals contain more pure colors than natural material because they contain more pure constituents. Laboratory production of opal calls for a very high temperature: natural opal is no longer being created because temperatures are not high enough. Even in the laboratory it is impossible to produce two identical opals. Production starts with the production of millions of tiny beads, each about 0.3 microns in diameter, and these eventually form the finished material. M Gilson’s most recent improvements involve the removal of all traces of water from synthetic opals, and this gets rid of cracks and helps to avoid some of the hazards associated with the natural material. With natural opals, it is interesting to note that material found at depth of more than six meters is often noticeably better than stones found near the surface.
Natural turquoise contains iron, and in some cases customers are disappointed when the iron turns green after a year or two. ‘Our own stones are pure turquoise, so this problem doesn’t arise’—but a process has now been developed so that iron can be introduced to the surface of synthetic turquoise.
With lapis, although pyrites (its inclusions) can be synthesized, M Gilson uses natural pyrites. ‘Each day nine hundred tons of natural pyrites are mined: I cannot compete with that!’ He is now successfully synthesizing coral and used calcite which is now being mined in France.
In answer to a question whether he could suggest any methods of testing stones to tell the difference between real and synthetic specimens, he said: ‘We work on developing new scientific products, but when it comes to identification you are the experts.’ Asked whether it was his intention to produce stones so similar to the natural product that they could not be detected, he replied: ‘We are not competing with Nature but merely trying to improve on it by producing more pure stones—more beautiful ones for the jeweler to work with.’
Mr Alec Farn asked if M Gilson had produced any emeralds without chromium but with the addition of vanadium, and M Gilson replied that he had not—and even if it was done, could the result be described as emerald?’ ‘If people want chromium in emerald, then why shouldn’t we give it to them?’
Offering a tip for improving opals, M Gilson said that if soaked over night in ethyl alcohol all moisture in the stone would be driven out and the color improved—but it was essential not to do this if the stone was a triplet! And in reply to an enquiry whether he had carried out any experiment on the jadeite family, he smiled and said: ‘Yes, we are working on this problem.’
When asked how long he had been trying to make synthetic stones before he had his first success, he said he took fifteen years to succeed with emerald, ten years with opal, and eight years with turquoise: and because of slow reactions and the length of time it took to grow a single crystal before it was known whether or not the experiment was a success, research was becoming more difficult and expensive. Some members of the audience were surprised when M Gilson mentioned that his main business was not the production of synthetic gemstones but the manufacture of about nine tons of ceramics each month for industrial use.
(via The Journal of Gemmology, Vol.XVI, No.7, July 1979)
A report on M. Pierre Gilson’s talk
On the 11th October, 1978, a talk was given to members of the Association by M Pierre Gilson on ‘Precious Stones of the Future from the Laboratory’ in the Geological Museum Cinema Theatre, South Kensington. The theatre was full when the proceedings were opened and the speaker was introduced by the vice-chairman, Dr David Callaghan, FGA, who said M Gilson produced the very best that man could produce and was able to do in a relatively short time things which Nature took very much longer to achieve; his talent and the vast range of materials that he was producing were quite fantastic.
M Gilson’s talk then took the form of a running commentary no the hundred or so slides which he showed during the evening and he left few people in doubt about the progress made in the last fifty or sixty years. He reminded the audience that Verneuil was the first to make synthetic ruby and sapphire at the beginning of the century: with his relatively simple method he was able to produce a boule in one of several colors in a matter of three hours or so, and his synthetic corundum was soon used to make the jewels in watches.
In contrast, M Gilson’s company takes as long as nine months to grow synthetic emeralds. They start with a seed—synthetic material of the highest quality—and grow it as a non-stop process for nine months. A continuous supply of electricity is essential, because it is important to allow crystallization to take place at a constant temperature if good crystals are to be grown. Accordingly arrangements have been made to ensure that the company is guaranteed a supply of electricity privately in case there should be a failure in the public supply due to breakdown or perhaps a strike.
But it is not just a matter of having the right equipment and know how: experimentation also is necessary. Before success in making synthetic turquoise was achieved, thirty different phosphates had to be crystallized.
The equipment now used in the Gilson laboratories is very sophisticated and quite advanced. In order to study the size and formation of the tiny ‘beads’ which make up such gemstones as emeralds an electron microscope is used. A spectrophotometer is another essential piece of equipment, because it is important to be able to control absorption to within one part per million.
With synthetic emeralds M Gilson has found it beneficial to cut at a specific angle in relation to the seed crystal on which the new material has been grown. He used slides to explain that the main difference between synthetic and natural emerald lies in the nature of the inclusions. In the synthetic material the ‘veil’ is twisted, whereas in the natural stone it is straight. He added that Nature produced only one good emerald for every million crystals formed: in the laboratory it was essential to have a very much higher success rate. Emerald production in the Gilson laboratory takes precisely nine months, since, if you wait any longer, crystallization may have stopped. A simple—but impractical! –test to distinguish between natural and synthetic emerald was mentioned: if you heat it to one thousand degrees and it turns white when it cools, you know it is natural. He added that the hardness of emerald was affected by the extent of inclusions in a given stone.
Opal was next discussed. Opal is pure silica: it acts like a prism and the colors which can be seen are pure spectral colors. Gilson synthetic opals contain more pure colors than natural material because they contain more pure constituents. Laboratory production of opal calls for a very high temperature: natural opal is no longer being created because temperatures are not high enough. Even in the laboratory it is impossible to produce two identical opals. Production starts with the production of millions of tiny beads, each about 0.3 microns in diameter, and these eventually form the finished material. M Gilson’s most recent improvements involve the removal of all traces of water from synthetic opals, and this gets rid of cracks and helps to avoid some of the hazards associated with the natural material. With natural opals, it is interesting to note that material found at depth of more than six meters is often noticeably better than stones found near the surface.
Natural turquoise contains iron, and in some cases customers are disappointed when the iron turns green after a year or two. ‘Our own stones are pure turquoise, so this problem doesn’t arise’—but a process has now been developed so that iron can be introduced to the surface of synthetic turquoise.
With lapis, although pyrites (its inclusions) can be synthesized, M Gilson uses natural pyrites. ‘Each day nine hundred tons of natural pyrites are mined: I cannot compete with that!’ He is now successfully synthesizing coral and used calcite which is now being mined in France.
In answer to a question whether he could suggest any methods of testing stones to tell the difference between real and synthetic specimens, he said: ‘We work on developing new scientific products, but when it comes to identification you are the experts.’ Asked whether it was his intention to produce stones so similar to the natural product that they could not be detected, he replied: ‘We are not competing with Nature but merely trying to improve on it by producing more pure stones—more beautiful ones for the jeweler to work with.’
Mr Alec Farn asked if M Gilson had produced any emeralds without chromium but with the addition of vanadium, and M Gilson replied that he had not—and even if it was done, could the result be described as emerald?’ ‘If people want chromium in emerald, then why shouldn’t we give it to them?’
Offering a tip for improving opals, M Gilson said that if soaked over night in ethyl alcohol all moisture in the stone would be driven out and the color improved—but it was essential not to do this if the stone was a triplet! And in reply to an enquiry whether he had carried out any experiment on the jadeite family, he smiled and said: ‘Yes, we are working on this problem.’
When asked how long he had been trying to make synthetic stones before he had his first success, he said he took fifteen years to succeed with emerald, ten years with opal, and eight years with turquoise: and because of slow reactions and the length of time it took to grow a single crystal before it was known whether or not the experiment was a success, research was becoming more difficult and expensive. Some members of the audience were surprised when M Gilson mentioned that his main business was not the production of synthetic gemstones but the manufacture of about nine tons of ceramics each month for industrial use.
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