According to World Wealth Report (Merrill Lynch + Capgemini), for high net worth individuals, jewelry falls into the third category for investments of passion.
More info @ http://www.us.capgemini.com/worldwealthreport07/wwr_pressrelease.asp?ID=629
Monday, July 16, 2007
The Pleasures Of Discovery
(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)
Sinhalite
Less than a year after the paper on taaffeite was read before the Mineralogical Society, Dr Claringbull was able to announce the establishment of yet another new gem mineral, which he named sinhalite from its origin in Ceylon. But on this occasion we were spectators rather than protagonists, though we were able to provide many specimens to aid the work, as sinhalite had been knocking around for sometime under the disguise of brown peridot. Robert Webster indeed nobly sacrificed part of his only specimen for Dr Hey to analyze. Whereas, when the taaffeite paper was read, all we had to show was two small cut specimens, Claringbull had a score of sinhalites to show (one giant of 75 carats) which had crept from their wrongly labeled packets for the occasion. There was even a small pebble of sinhalite which had been picked from a sample of illam by Dr E H Rutland.
Credit for the sinhalite discovery belongs properly to Dr George Switzer of the Smithsonian Institution, who took an X-ray powder photograph of scrapings from the girdle of a ‘brown peridot’ in the U.S Museum collection and found spacings which clearly differed from those of olivine. Knowing this, Dr W F Foshag (Switzer’s chief in the Institution) cast doubts on a specimen of ‘brown peridot’ in the Natural History Museum when Dr Claringbull was showing him round the mineral gallery, which gave rise to an energetic attack on the problem.
Sinhalite contains no silica, being a magnesium alumunium borate, MgAlBO4. Like peridot, it is orthorhombic, and its refractive indices, birefringence and density are very close to those of brown iron-rich peridots or olivines which are occasionally met with in Arizona and elsewhere; the chief difference being in the b index, which in peridot is nearly mid-way between the greatest and least indices, while sinhalite is clearly negative in sign. The absorption spectra are also very similar in the two minerals, but sinhalite shows an extra band at 4630 Angstrom. Sinhalites have been found in packets of golden zircons and of yellow chrysoberyls—they vary in color from pale straw yellow, but at their best are very attractive, being clean, transparent, and obtainable in important sizes. In fact, of all the newly discovered stones that I am talking about this evening sinhalite is the only one that has the slightest commercial importance. On the ‘anything you can do’ principle which I mentioned earlier, it was Burma which provided the first well-shaped sinhalite crystal, which C J Payne had the privilege of measuring.
Painite
In painite we have the rarest mineral of them all: in fact I find it rather amusing, considering that no cut stone exists (2007: today there are cut specimens available at affordable prices ), that a description of the stone occurs in at least five books on gemstones. The original dark red crystal, well-formed though rather waterworn, was found in one of the small ruby mines near Ohngaing village in the Mogok district of Burma. Mr A C D Pain, who suspected it might be something new, sent it to the laboratory for testing. The crystal at first sight looked as though it were tetragonal, but C J Payne, finding the prism angles to be exactly 60º realized that in fact it was hexagonal. It weighed 8.5 carats. The density was found to be 4.01 and the refractive indices 1.8159 for the ordinary and 1.7875 for the extraordinary ray, giving a birefringence of 0.0284. The hardness was measured as 8 on Moh’s scale by an indentation method. The dichroism showed a brownish red for the ordinary ray and deep ruby red for the extraordinary.
Permission was given for a thin slice to be removed from the base of the crystal for Claringbull and Hey to carry out the necessary X-ray and chemical work. Analysis showed the mineral to be borosilicate of calcium and aluminium, but it proved difficult to ascribe to it a definite formula. The specimen was justly named after its discoverer, and presented by him to the Museum where most of the work on it was done.
Chromium lines were visible in the red end of the spectrum, and the color was probably due to this, at least in part. In confirmation of this, the stone showed a red glow under crossed filters. It is difficult to judge how attractive a cut painite might be. In bulk, the color was too deep to be effective, but one might guess that small stones might look very much like Siam rubies.
The Pleasure Of Discovery (continued)
(being the substance of a talk given to the Gemmological Association of Great Britain at Goldsmith’s Hall on 29th October, 1973)
Sinhalite
Less than a year after the paper on taaffeite was read before the Mineralogical Society, Dr Claringbull was able to announce the establishment of yet another new gem mineral, which he named sinhalite from its origin in Ceylon. But on this occasion we were spectators rather than protagonists, though we were able to provide many specimens to aid the work, as sinhalite had been knocking around for sometime under the disguise of brown peridot. Robert Webster indeed nobly sacrificed part of his only specimen for Dr Hey to analyze. Whereas, when the taaffeite paper was read, all we had to show was two small cut specimens, Claringbull had a score of sinhalites to show (one giant of 75 carats) which had crept from their wrongly labeled packets for the occasion. There was even a small pebble of sinhalite which had been picked from a sample of illam by Dr E H Rutland.
Credit for the sinhalite discovery belongs properly to Dr George Switzer of the Smithsonian Institution, who took an X-ray powder photograph of scrapings from the girdle of a ‘brown peridot’ in the U.S Museum collection and found spacings which clearly differed from those of olivine. Knowing this, Dr W F Foshag (Switzer’s chief in the Institution) cast doubts on a specimen of ‘brown peridot’ in the Natural History Museum when Dr Claringbull was showing him round the mineral gallery, which gave rise to an energetic attack on the problem.
Sinhalite contains no silica, being a magnesium alumunium borate, MgAlBO4. Like peridot, it is orthorhombic, and its refractive indices, birefringence and density are very close to those of brown iron-rich peridots or olivines which are occasionally met with in Arizona and elsewhere; the chief difference being in the b index, which in peridot is nearly mid-way between the greatest and least indices, while sinhalite is clearly negative in sign. The absorption spectra are also very similar in the two minerals, but sinhalite shows an extra band at 4630 Angstrom. Sinhalites have been found in packets of golden zircons and of yellow chrysoberyls—they vary in color from pale straw yellow, but at their best are very attractive, being clean, transparent, and obtainable in important sizes. In fact, of all the newly discovered stones that I am talking about this evening sinhalite is the only one that has the slightest commercial importance. On the ‘anything you can do’ principle which I mentioned earlier, it was Burma which provided the first well-shaped sinhalite crystal, which C J Payne had the privilege of measuring.
Painite
In painite we have the rarest mineral of them all: in fact I find it rather amusing, considering that no cut stone exists (2007: today there are cut specimens available at affordable prices ), that a description of the stone occurs in at least five books on gemstones. The original dark red crystal, well-formed though rather waterworn, was found in one of the small ruby mines near Ohngaing village in the Mogok district of Burma. Mr A C D Pain, who suspected it might be something new, sent it to the laboratory for testing. The crystal at first sight looked as though it were tetragonal, but C J Payne, finding the prism angles to be exactly 60º realized that in fact it was hexagonal. It weighed 8.5 carats. The density was found to be 4.01 and the refractive indices 1.8159 for the ordinary and 1.7875 for the extraordinary ray, giving a birefringence of 0.0284. The hardness was measured as 8 on Moh’s scale by an indentation method. The dichroism showed a brownish red for the ordinary ray and deep ruby red for the extraordinary.
Permission was given for a thin slice to be removed from the base of the crystal for Claringbull and Hey to carry out the necessary X-ray and chemical work. Analysis showed the mineral to be borosilicate of calcium and aluminium, but it proved difficult to ascribe to it a definite formula. The specimen was justly named after its discoverer, and presented by him to the Museum where most of the work on it was done.
Chromium lines were visible in the red end of the spectrum, and the color was probably due to this, at least in part. In confirmation of this, the stone showed a red glow under crossed filters. It is difficult to judge how attractive a cut painite might be. In bulk, the color was too deep to be effective, but one might guess that small stones might look very much like Siam rubies.
The Pleasure Of Discovery (continued)
Ekanite
Chemistry: Metamict-Calcium thorium silicate
Crystal system: Amorphous from Tetragonal; usually micro crystals; rarely large.
Color: Transparent to translucent; metamict: green, yellow, light brown; crystalline: yellow-red; phenomena: may show 4-rayed star.
Hardness: 6.0 – 6.5
Cleavage: -
Specific gravity: 3.28
Refractive index: 1.597 metamict; SR.
Luster: Vitreous.
Dispersion: -
Dichroism: -
Occurrence: Gem gravels of Sri Lanka; some crystalline material found in Canada.
Notes
Found in 1953; mildly radioactive; may be cut as collector’s stone.
Crystal system: Amorphous from Tetragonal; usually micro crystals; rarely large.
Color: Transparent to translucent; metamict: green, yellow, light brown; crystalline: yellow-red; phenomena: may show 4-rayed star.
Hardness: 6.0 – 6.5
Cleavage: -
Specific gravity: 3.28
Refractive index: 1.597 metamict; SR.
Luster: Vitreous.
Dispersion: -
Dichroism: -
Occurrence: Gem gravels of Sri Lanka; some crystalline material found in Canada.
Notes
Found in 1953; mildly radioactive; may be cut as collector’s stone.
Sunday, July 15, 2007
200 Top Art Collectors
The Art News 200 top art collectors list @ http://www.artnewsonline.com/issues/article.asp?art_id=2311
European Commission May Reconsider Decision To Close SoC Investigations
Chaim Even-Zohar writes about European Commission's (EC) views regarding De Beers’ Supplier of Choice (SoC), background to the judgment + the impact + other viewpoints @ http://www.idexonline.com/portal_FullEditorial.asp
Jewel Thieves Make Off With Huge Haul
(via ABC news) London thieves show up in Bentley, make off with millions worth of jewelry.
The victim: Graff Jewellers!
More info @ http://abcnews.go.com/International/wireStory?id=3368938
The victim: Graff Jewellers!
More info @ http://abcnews.go.com/International/wireStory?id=3368938
Who Is Smiling?
Economist writes:
Riches do not necessarily make happiness, but a poll of 130 countries by Gallup found more people in wealthy places (America, Europe, Japan, Saudi Arabia) consider themselves happy, while those in poor countries (in Africa especially) generally do not. A map of the results, therefore, looks rather like an income plot of the world. There are a few exceptions. Mid-income Costa Ricans and Venezuelans are among the happiest on the planet. Georgians and Armenians, although not terribly poor, are among the glummest.
More info @http://www.economist.com/daily/chartgallery/displaystory.cfm?story_id=9490466
Riches do not necessarily make happiness, but a poll of 130 countries by Gallup found more people in wealthy places (America, Europe, Japan, Saudi Arabia) consider themselves happy, while those in poor countries (in Africa especially) generally do not. A map of the results, therefore, looks rather like an income plot of the world. There are a few exceptions. Mid-income Costa Ricans and Venezuelans are among the happiest on the planet. Georgians and Armenians, although not terribly poor, are among the glummest.
More info @http://www.economist.com/daily/chartgallery/displaystory.cfm?story_id=9490466
The Pleasures Of Discovery
(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)
The war
When Munich made it clear that war must inevitably come, Payne joined the Territorial Army and was trained as a gunner, whilst I enrolled with the Auxiliary Fire Service in London. When war was declared Payne was called up at once and spent the next few years fighting with the Eighth Army, rejoining the laboratory in September, 1945, just in time to prevent my being totally submerged in a sea of pearl testing. I was able to carry on with such testing work as there was with the aid of Sgt Stelling, a stalwart commissionaire, who had been taken on for the holiday period but who stayed for the ‘duration’. Actually, after the initial shock of war and the London ‘blitz’, the amount of testing work became quite heavy for one person. The number of tests undertaken dropped from the 1938 figure of 776 to 531 in 1939 and 323 in 1940, but had risen to 782 in 1944 and to 1062 in 1945. It was in 1946 that the really great expansion began and we enlisted the help of Robert Webster and Alec Farn, which completed the ‘Phalanx of Four’ which coped with the strenuous testing work of the next 25 years.
I mustn’t dwell on those war years, as I want to carry on with the story of discovery of new gem minerals, but a few points perhaps may be worth recalling.
As a safety precaution, our committee had moved our valuable X-ray equipment to a basement belonging to Johnson, Matthey & Co in Poland Street. This made the testing of undrilled and part-drilled pearls a very time consuming business, as I had to go down to Poland Street to take the photographs, and then post back to the laboratory to develop them.
The laboratory had several ‘near misses’ with bombs and fire, with minor damage. On the worst occasion I was luckily fighting a fire nearby and obtained permission to see how things were in the lab. A large cupboard full of chemicals had fallen on its face, making a truly unwholeseome mess on the floor. All I could do at the time was to pick up the small bottle containing the spontaneously inflammable yellow phosphorus, which I could see glowing in the dark, and put it into a bucket of water to wait for the morrow. I also had to comfort as best I could our diminutive housekeeper and his tearful wife, who had been sleeping each under one of our endoscopes when the bomb fell, and awoke to find that the apparatus had fallen on and around their legs. It required a good deal of cannibalization from other endoscopes to get ours into working order again.
During this war period I was able to do some useful work on the classification of diamond absorption and fluorescence, the distinction between pyrope and red spinel, etc. I also became aware for the first time of the advantages of the Becke 2458 prism spectroscope for spotting purposes, and with its aid discovered the ‘difficult’ absorption spectrum of turquoise, which has
since proved extremely useful. But now I must resume my main narrative.
Taaffeite
The discovery of the new gem mineral Taaffeite reads like a gemological fairy tale. Count Taaffe, only son of the 12th Viscount Taaffe of Corran, Baron of Ballymote in County Sligo, Ireland, was born in Bohemia in 1898, and died in Dublin in 1967. He was the first of his family to be allowed to return to Ireland after its long exile in Bohemia and Austria. Taaffe was a keen amateur both of gemology and astronomy, and found it both profitable and interesting to peddle in gemstones. Amongst his sources for inexpensive stones were the boxes of addments which jewelers keep behind their counters, finding them useful for jobbing purposes. In October 1945 he spent some days looking through the boxes belong to a friendly jeweler, Mr Robert Dobbie, and paid him £14 for the stones which interested him, which were mostly broken out of jewelry: badly rubbed or chipped in many cases.
Taffee worked with meager equipment, but made very effective use of what he did possess. He had no refractometer and no accurate balance. His chief instrument was a Bausch and Lomb binocular microscope without a stage, giving a magnification of 21 diameters.
His first steps, to which he attached great importance, in tackling a mixed batch of stones such as the lot from Mr Dobbie, was to clean the stones very thoroughly and then divide them by eye into batches according to color. He then examined each stone very carefully, holding it in tongs an scrutinizing it from all angles over a sheet of white paper. The illumination was a flexible desk lamp with a 100 watt bulb.
The stone which, incredibly, was later found to belong to a new mineral species was amongst a group of violet, mauve, and lilac colored stones. These were mostly spinels, but the stone in question showed in certain directions distinct signs of double refraction. In his words, ‘every speck of dust on the back and every scratch appeared double, like on a badly wobbled snapshot’. Since, as we now know, the stone had a D.R of only 0.005 and weighed only 1.42 carats, this was a remarkably acute piece of observation. He confirmed that the stone was birefringent by a test between crossed nicols, took a remarkably good density measurement (the average of ten attempts, using a hand-held balance) and finally on November 1st he posted the stone to me at the laboratory with a covering letter: ‘This time a new riddle: what is this mauve stone? It seems to me to answer all the characteristics of spinel, yet it shows double refraction: doubling of facets visible under the Greenough, extinction when polarized, though with queer color effects. Could anomalous double refraction be so strong? R.I too high for topaz, too low for corundum. What is it?’
The stone as received weighed 1.419 carats. Its shape suggested that it had been cut in Ceylon. The refractive indices were 1.718 for the extraordinary ray and 1.723 for the ordinary ray—thus the stone was uniaxial negative. It gave a clear uniaxial interference figure through the table facet. The density as then determined by hydrostatic weighing in ethylene dibromide was 3.621—later corrected to 3.613 by our Clerici solution flotation method, using blue spinels as indicators, one slightly denser and the other a little less dense than the taaffeite. The absorption spectrum was weak, but resembled that of blue spinel very closely.
I replied to Count Taaffe on November 5th, stating our findings and asking permission to have an X-ray analysis made if possible without harming the stone.
Preliminary X-ray tests carried out by Dr Claringbull confirmed the optical indications that the stone could not be spinel. To enable more X-ray and chemical work to be carried out Count Taaffe courageously agreed to having first one slice and then another removed from the culet region, stipulating only that the remains of his historic little stone be returned to him as a faceted gem. This work most skillfully carried out by Charles Mathews Lapidaries Ltd, the stone being reduced first to 0.95 and then to 0.56 carat. With a little imagination one can appreciate Taaffe’s feelings, knowing that he had discovered something quite new to science, but with only one small specimen as the representative of the new species.
On small crushed fragments from the stone X-ray powder, rotation and oriented Laue photographs were taken, showing the mineral to be hexagonal and to belong to the hexagonal trapezohedral class of symmetry—a class to which only ‘high’ quartz (formed above 573ºC) is known to belong. Preliminary analysis showed the presence of magnesium, alumunium and beryllium, and the final analysis, which was not completed until 1951, and was carried out by Dr Hey on only 6.16 milligrams of material, gave the essential formula as MgO.BeO.2Al2O3—that is, intermediate in composition between spinel and chrysoberyl. The ‘Oscars’ were mounting up for taaffeite: it belonged to a very rare class of crystal symmetry; and it was the only mineral known to contain both beryllium and magnesium as essential constituents. Data for an artificial compound of similar composition which were published in 1946 showed only a rough resemblance to those for taaffeite.
Naturally we kept a sharp lookout for further specimens, and examined every pale mauve spinel we could lay our hands on with extreme care, but it was not until October 1949 that the second taaffeite came to light, the honor and credit falling to C J Payne. He was working rather late in the laboratory on an interesting collection of 104 stones (mostly from Ceylon) sent in by a dealer for a routine test. There were a number of green sapphires and pale blue spinels and one kornerupine, which served as a curtain-raiser for a pale mauve stone weighing 0.86 carat which gave what appeared to be a taaffeite reading on the refractrometer. This was confirmed by the observation of a uniaxial interference figure. Payne was naturally enormously excited by his discovery after four years of searching, and rang me up at Goldsmith’s Hall where Webster and I were attending at a Gemological Exhibition being held there. Next day I was on holiday in Devon and had to carry on some cautious haggling by telephone with Payne as intermediary. At any cost, we had to have that stone. By using the kornerupine as a stalking horse we were able to obtain the two stones for £20.
After publication of the taaffeite story in Nature, the gemological journals, and Mineralogical Magazine in 1951, keen gemologists the world over were on the lookout for further specimens, but taaffeite number three did not appear until Christmas Eve, 1957, when it was spotted in the New York Gem Laboratory by our friend Robert Crowningshield. A further ten years were to elapse before a fourth specimen was identified in America following an article on the subject by George Bruce in the Modern Jeweler. This was a ‘giant’ of 5.34 carats, and, surprisingly, dark brownish purple in color.
In 1963 came a report that crystals of the mineral up to 1cm in length had been found in the Hunnan Province of China, though not of gem quality, and specimens are to be seen in the Mineralogical Museum of the Academy of Sciences in Moscow. Since then, tiny green crystals found in the Musgrave Ranges of Central Australia were found to be a ‘polytype’ of taaffeite in which nine subcells instead of four make up the unit cell, giving threefold in place of sixfold symmetry to X-ray patterns. One day, I am sure, a pebble of taaffeite will be found in the Ceylon gem gravels.
Of the four cut taaffeites mentioned, the original specimen was purchased by Mr R K Mitchell after Taaffe’s death, together with other stones from his small collection; the stone discovered by Payne is where it should be—in the Natural History Museum in South Kensington—while the American stones are apparently both in the hands of a private collector, though one was on show for a year at the Smithsonian Institute in Washington.
(continued)
(being the substance of a talk given to the Gemmological Association of Great Britain at Goldsmith’s Hall on 29th October, 1973)
The war
When Munich made it clear that war must inevitably come, Payne joined the Territorial Army and was trained as a gunner, whilst I enrolled with the Auxiliary Fire Service in London. When war was declared Payne was called up at once and spent the next few years fighting with the Eighth Army, rejoining the laboratory in September, 1945, just in time to prevent my being totally submerged in a sea of pearl testing. I was able to carry on with such testing work as there was with the aid of Sgt Stelling, a stalwart commissionaire, who had been taken on for the holiday period but who stayed for the ‘duration’. Actually, after the initial shock of war and the London ‘blitz’, the amount of testing work became quite heavy for one person. The number of tests undertaken dropped from the 1938 figure of 776 to 531 in 1939 and 323 in 1940, but had risen to 782 in 1944 and to 1062 in 1945. It was in 1946 that the really great expansion began and we enlisted the help of Robert Webster and Alec Farn, which completed the ‘Phalanx of Four’ which coped with the strenuous testing work of the next 25 years.
I mustn’t dwell on those war years, as I want to carry on with the story of discovery of new gem minerals, but a few points perhaps may be worth recalling.
As a safety precaution, our committee had moved our valuable X-ray equipment to a basement belonging to Johnson, Matthey & Co in Poland Street. This made the testing of undrilled and part-drilled pearls a very time consuming business, as I had to go down to Poland Street to take the photographs, and then post back to the laboratory to develop them.
The laboratory had several ‘near misses’ with bombs and fire, with minor damage. On the worst occasion I was luckily fighting a fire nearby and obtained permission to see how things were in the lab. A large cupboard full of chemicals had fallen on its face, making a truly unwholeseome mess on the floor. All I could do at the time was to pick up the small bottle containing the spontaneously inflammable yellow phosphorus, which I could see glowing in the dark, and put it into a bucket of water to wait for the morrow. I also had to comfort as best I could our diminutive housekeeper and his tearful wife, who had been sleeping each under one of our endoscopes when the bomb fell, and awoke to find that the apparatus had fallen on and around their legs. It required a good deal of cannibalization from other endoscopes to get ours into working order again.
During this war period I was able to do some useful work on the classification of diamond absorption and fluorescence, the distinction between pyrope and red spinel, etc. I also became aware for the first time of the advantages of the Becke 2458 prism spectroscope for spotting purposes, and with its aid discovered the ‘difficult’ absorption spectrum of turquoise, which has
since proved extremely useful. But now I must resume my main narrative.
Taaffeite
The discovery of the new gem mineral Taaffeite reads like a gemological fairy tale. Count Taaffe, only son of the 12th Viscount Taaffe of Corran, Baron of Ballymote in County Sligo, Ireland, was born in Bohemia in 1898, and died in Dublin in 1967. He was the first of his family to be allowed to return to Ireland after its long exile in Bohemia and Austria. Taaffe was a keen amateur both of gemology and astronomy, and found it both profitable and interesting to peddle in gemstones. Amongst his sources for inexpensive stones were the boxes of addments which jewelers keep behind their counters, finding them useful for jobbing purposes. In October 1945 he spent some days looking through the boxes belong to a friendly jeweler, Mr Robert Dobbie, and paid him £14 for the stones which interested him, which were mostly broken out of jewelry: badly rubbed or chipped in many cases.
Taffee worked with meager equipment, but made very effective use of what he did possess. He had no refractometer and no accurate balance. His chief instrument was a Bausch and Lomb binocular microscope without a stage, giving a magnification of 21 diameters.
His first steps, to which he attached great importance, in tackling a mixed batch of stones such as the lot from Mr Dobbie, was to clean the stones very thoroughly and then divide them by eye into batches according to color. He then examined each stone very carefully, holding it in tongs an scrutinizing it from all angles over a sheet of white paper. The illumination was a flexible desk lamp with a 100 watt bulb.
The stone which, incredibly, was later found to belong to a new mineral species was amongst a group of violet, mauve, and lilac colored stones. These were mostly spinels, but the stone in question showed in certain directions distinct signs of double refraction. In his words, ‘every speck of dust on the back and every scratch appeared double, like on a badly wobbled snapshot’. Since, as we now know, the stone had a D.R of only 0.005 and weighed only 1.42 carats, this was a remarkably acute piece of observation. He confirmed that the stone was birefringent by a test between crossed nicols, took a remarkably good density measurement (the average of ten attempts, using a hand-held balance) and finally on November 1st he posted the stone to me at the laboratory with a covering letter: ‘This time a new riddle: what is this mauve stone? It seems to me to answer all the characteristics of spinel, yet it shows double refraction: doubling of facets visible under the Greenough, extinction when polarized, though with queer color effects. Could anomalous double refraction be so strong? R.I too high for topaz, too low for corundum. What is it?’
The stone as received weighed 1.419 carats. Its shape suggested that it had been cut in Ceylon. The refractive indices were 1.718 for the extraordinary ray and 1.723 for the ordinary ray—thus the stone was uniaxial negative. It gave a clear uniaxial interference figure through the table facet. The density as then determined by hydrostatic weighing in ethylene dibromide was 3.621—later corrected to 3.613 by our Clerici solution flotation method, using blue spinels as indicators, one slightly denser and the other a little less dense than the taaffeite. The absorption spectrum was weak, but resembled that of blue spinel very closely.
I replied to Count Taaffe on November 5th, stating our findings and asking permission to have an X-ray analysis made if possible without harming the stone.
Preliminary X-ray tests carried out by Dr Claringbull confirmed the optical indications that the stone could not be spinel. To enable more X-ray and chemical work to be carried out Count Taaffe courageously agreed to having first one slice and then another removed from the culet region, stipulating only that the remains of his historic little stone be returned to him as a faceted gem. This work most skillfully carried out by Charles Mathews Lapidaries Ltd, the stone being reduced first to 0.95 and then to 0.56 carat. With a little imagination one can appreciate Taaffe’s feelings, knowing that he had discovered something quite new to science, but with only one small specimen as the representative of the new species.
On small crushed fragments from the stone X-ray powder, rotation and oriented Laue photographs were taken, showing the mineral to be hexagonal and to belong to the hexagonal trapezohedral class of symmetry—a class to which only ‘high’ quartz (formed above 573ºC) is known to belong. Preliminary analysis showed the presence of magnesium, alumunium and beryllium, and the final analysis, which was not completed until 1951, and was carried out by Dr Hey on only 6.16 milligrams of material, gave the essential formula as MgO.BeO.2Al2O3—that is, intermediate in composition between spinel and chrysoberyl. The ‘Oscars’ were mounting up for taaffeite: it belonged to a very rare class of crystal symmetry; and it was the only mineral known to contain both beryllium and magnesium as essential constituents. Data for an artificial compound of similar composition which were published in 1946 showed only a rough resemblance to those for taaffeite.
Naturally we kept a sharp lookout for further specimens, and examined every pale mauve spinel we could lay our hands on with extreme care, but it was not until October 1949 that the second taaffeite came to light, the honor and credit falling to C J Payne. He was working rather late in the laboratory on an interesting collection of 104 stones (mostly from Ceylon) sent in by a dealer for a routine test. There were a number of green sapphires and pale blue spinels and one kornerupine, which served as a curtain-raiser for a pale mauve stone weighing 0.86 carat which gave what appeared to be a taaffeite reading on the refractrometer. This was confirmed by the observation of a uniaxial interference figure. Payne was naturally enormously excited by his discovery after four years of searching, and rang me up at Goldsmith’s Hall where Webster and I were attending at a Gemological Exhibition being held there. Next day I was on holiday in Devon and had to carry on some cautious haggling by telephone with Payne as intermediary. At any cost, we had to have that stone. By using the kornerupine as a stalking horse we were able to obtain the two stones for £20.
After publication of the taaffeite story in Nature, the gemological journals, and Mineralogical Magazine in 1951, keen gemologists the world over were on the lookout for further specimens, but taaffeite number three did not appear until Christmas Eve, 1957, when it was spotted in the New York Gem Laboratory by our friend Robert Crowningshield. A further ten years were to elapse before a fourth specimen was identified in America following an article on the subject by George Bruce in the Modern Jeweler. This was a ‘giant’ of 5.34 carats, and, surprisingly, dark brownish purple in color.
In 1963 came a report that crystals of the mineral up to 1cm in length had been found in the Hunnan Province of China, though not of gem quality, and specimens are to be seen in the Mineralogical Museum of the Academy of Sciences in Moscow. Since then, tiny green crystals found in the Musgrave Ranges of Central Australia were found to be a ‘polytype’ of taaffeite in which nine subcells instead of four make up the unit cell, giving threefold in place of sixfold symmetry to X-ray patterns. One day, I am sure, a pebble of taaffeite will be found in the Ceylon gem gravels.
Of the four cut taaffeites mentioned, the original specimen was purchased by Mr R K Mitchell after Taaffe’s death, together with other stones from his small collection; the stone discovered by Payne is where it should be—in the Natural History Museum in South Kensington—while the American stones are apparently both in the hands of a private collector, though one was on show for a year at the Smithsonian Institute in Washington.
(continued)
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