An incredible and sensational event has occurred in the realm of gemstones (although personally I expected it happen for a long time): a group of U.S. researchers at the Carnegie Institution in Washington led by Russell Hemley has succeeded in growing huge clear diamonds using a methane-hydrogen mixture, writes Professor Alexander Portnov, Academician of the Russian Academy of Natural Sciences, in his article published in the Sovetskaya Rossiya Daily, which is given below abridged. Their weight, according to the author, is striking and is up to 32 carats, but Hemley states that his technique permits to grow diamonds weighing over a dozen kg, up to a football in size and bigger, provided they get into a micro-wave oven. I would like to remind that Cullinan, the largest gem-quality diamond found in South Africa in 1905, weighed 605 grams and was as a fist in size.
The epoch of the King of Gems has come to an end in a microwave oven filled with a methane-hydrogen mixture. I have been expecting this moment to come since 1982, when my article was published in the Reports of the USSR Academy of Sciences, where it described a model of producing diamonds in a С-Н-О system using methane-hydrogen gas that formed kimberlites. Understanding the importance of such a discovery, I wrote a letter to the Presidium of the USSR Academy of Sciences regarding the practical feasibility of diamond synthesis from gas. But…no reply came, and up to now, my colleagues - geologists, professors and academicians - keep on telling a childish fairy-tail about mysterious ‘explosion pipes’ bringing up diamonds from the ‘rock-caves’ of the mantle in their thesis, articles and monographs.
By the way, at that remote time, the U.S. colleagues also refused to translate my article in the Reports about kimberlites as fluidizites, i.e. rocks generated in the presence of methane-hydrogen fluid. That was the instance when the thought was far ahead of the social and scientific mentality, and diamond crystallization in kimberlites from gas seemed impossible to geologists.
The geologists’ vision was suppressed because technical diamonds were successfully grown from graphite since 1953, using the technique proposed by Leipunski, a Soviet scientist. The technique was based on the difference in solubility between graphite and diamond in an iron-nickel melt. Graphite dissolved easily in the melt and saturated it with carbon. Diamond which was insoluble in the melt was quick to crystallize under the pressure of 10 000 bars and the temperature of 1400°C. As a result, tens of small diamond crystals grew through the graphite-metal pellets in high-pressure chambers within half a minute.
However, those were technical diamonds, a raw material for the abrasive industry. Tens of tons of such diamonds were manufactured around the world, they were dark in color, small in size, contained a lot of impurities and were not suitable for cutting and polishing. The main thing was that this crystallization process had nothing to do with the natural one. Nevertheless, the Soviet engineers in Novosibirsk tried to obtain gem-quality diamonds using this method. They developed a BARS apparatus which sometimes produced clear diamonds up to 2.5 carats in size. The installation yielded moderate amounts of gem-quality diamonds and mainly produced small technical diamonds.
After the disintegration of the USSR… Belarus has become a major synthetic diamond producer and owner of this hi-tech and lucrative production. 120 BARS installations purchased from Russia are making here small-size vivid-yellow or green color diamonds resembling natural stones. These bring in a hefty revenue to this small independent country: a one-carat polished synthetic diamond does not differ from a natural diamond and costs up to $1 000.
For a long time, gemstones – diamonds, rubies, sapphires, emeralds, pearls – were deemed to be a ‘stability island’ in the stormy ocean of theft and inflation. Presuming that family jewels do not lose value, many people purchase gems thinking that such a way of saving money is the most reliable. Is it really so?
In the early 20th century, there was launched large-scale synthesis of rubies and sapphires the chemical composition of which was very simple: aluminium oxide with admixture of chromium- or titanium oxide. This resulted in thousands of tons of valuable ‘dove blood’ quality rubies or expensive ‘cornflower blue’ color sapphires baked in furnaces like loaves of bread. Their value decreased hundreds and thousands of times, while only experts could distinguish a cheap synthetic piece from a natural stone, however not always.
Later on, this was followed by mass-scale synthesis of emerald, rock crystal, amethyst, citrine, red and blue spinel, turquoise, and malachite. Commercial production of pearls grown in pearl-shells was launched, and pearls were practically no different from the natural ones. As for quality, cheap synthetic gems are not inferior to natural gemstones and even feature better color, clearance, brilliance and bigger sizes.
For a long time, the value of diamonds has been the only thing which remained unchallenged. Nowadays, diamonds are mined all over Africa – in South Africa, Botswana, Namibia, Tanzania, Angola, and Zaire; African kimberlitic and alluvial deposits produce over 70 million carats annually. About 25 million carats are mined in Australia, 35 million in Russia, over 2 million in Canada; small quantities of diamonds are produced in Brazil, India and China. At present, global diamond output is 130 million carats; in other words, miners produce over 25 tons of diamonds every year. If we assume the average diamond price as $100 per carat, then this huge heap of wealth would amount to $13 billion.
However, diamond crystals are raw material only. They turn into real gems after time-taking processes of sorting, separating jewelry quality stones, their sawing, splitting, cutting, polishing and then evaluating. And here comes the most interesting – generating a new value. The matter is that the price of a polished diamond is a rather conventional notion. It stems from a traditional ages-long perception that diamonds are rare stones difficult to be cut and polished, and hence, their price is high. But are diamonds rare and really so expensive?
Nowadays, diamond mining and diamond cutting are a high-productive global process, a grandiose ‘diamond conveyor’ bringing sparkling heaps of stones to store counters in all countries. The world output is about 130 million carats. Gem-quality diamonds or transparent chips left from technical-quality diamonds account for 50 million carats, half of this quantity.
In the process of cutting, diamonds lose half of their weight: it means the conveyor yields about 20 million carats per year. One polished carat costs $1 000 to $2 000, but most of the quantity is 0.3 carat diamond melee priced less, so the value of polished diamonds made every year is about $15 billion. Experts strictly see to it that polished diamonds would not flood the market and get devalued.
The most common polished diamonds with a real ‘brilliant’ cut have 57 edges and weigh, on the average, 0.3 carats; in jewelry pieces there are also many cut diamonds of much smaller weight. Every year, hundreds of millions of polished diamonds enter the market, and their number is steadily growing. Within the last two decades, there have been manufactured over 5 billion polished diamonds, without counting polished diamond melee. Since 1985 only, 2 billion carats of diamonds have been mined, and half the quantity was of jewelry quality. Over the entire history, about 4 billion carats of rough diamonds have been extracted, half of which were of jewelry quality, so totally polished diamonds weigh one billion carats (200 tons). This quantity consists of 20 to 30 billion stones, and their total value is one trillion US dollars.
Nowadays, everybody on earth can have diamond jewelry to a sum of $200. But is it really so in practice? According to statistics, 70 percent of the Earth’s population has an income under $200 per month.
Major buyers of jewelry make about half a billion people, maximum 8 to 10 per cent of the global population. Thus, 30 billion polished diamonds accumulated by the mankind are circulating or being kept in the storerooms on the market, where the number of owners-sellers-buyers is approximately 500 million, i.e. 60 polished diamonds per capita.
It turns out there is a huge quantity of polished diamonds accumulated worldwide. The global market for today’s mass-conveyor production of polished diamonds is rather small and definitely glutted. It means that either the price for polished diamonds is too high or… that tens or even hundreds of millions of rough carats are kept in De Beers’ storehouses. The stones are probably bought up on a regular basis and fill the company’s safes to avoid overstocking in the jewelry market and prevent price collapse.
From time to time, false rumors are spread and made public to rouse interest to polished diamonds. The legend about the incredible value of ‘black diamonds’ is an example of such ‘disinfo.’ I will disappoint the owners: from time immemorial, black diamonds have been highly valued only for their viscosity (lack of brittleness characteristic of white diamonds), and that is why, they were used exclusively in bore bits, because while boring white diamonds fracture and split off.
In 1969, Boris Deryagin, Corresponding Member of the USSR Academy of Sciences, synthesized diamonds from a methane-hydrogen mixture under the pressure of less than one atmosphere. The Leipunski diagram demonstrated that graphite transforms into diamond only under high pressure. The diagram was cited in all textbooks. Looking at that diagram geologists believed that diamonds were crystallized billions of years ago in the Earth mantle. They did not understand that carbon in the mantle exists in the form of methane and not graphite, and the ‘graphite-diamond’ diagram had nothing to do with the geology of kimberlites.
Today, there exist dozens of patents for producing diamond film coatings from methane-hydrogen gas under low pressures. The geological and geochemical data allowed me to set forth a hypothesis about the origin of diamond-bearing kimberlite pipes when platforms are punched by giant methane-hydrogen ‘bubbles’ generated by the Earth degassing process. In the course of this, diamond crystals crop up not in the mantle but in the pipes due to lower mantle pressure and partial methane oxidation. Instead of low-quality diamonds obtained for technical applications from a metal melt, diamonds from methane are notable for their purity and clarity. No doubt, that De Beers spared no money to acquire interesting gas synthesis projects to hide them in its safes.
But the problem of simple and low-cost synthesis of jewelry-quality diamonds has now been brilliantly solved by the Americans, and this can be regarded as a tragedy for the currently operating diamond mining and jewelry industries. Right now, high-quality jewelry crystals up to 32 carats are obtained from gas! Soon, the weight of gem-quality diamonds will reach dozens of kilos! The success of the Americans can be attributed to the fact that they followed the natural process.
The synthesis of diamonds from a melt has no future; it has no analogues in nature and is obsolete. Soon, mining diamonds from kimberlite pipes and alluvial deposits will be of no sense. Right now, synthetic diamonds account for up to 10 percent of polished diamonds. In 10 years, half of polished diamonds will be synthetic. In future, cheap synthetic diamonds will turn into bijouterie like rubies, sapphires, fianites, yttrium garnets and moissanites. Inflation will strike banks and state repositories: the once famous treasures will lose their real value and preserve their historical significance only. The ‘stability island’ of gemstones that existed exclusively by virtue of polished diamonds will be lost like Atlantis. And the mankind will be left to continue its eternal search for ‘everlasting values.’
