lab created ruby/sapphire
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by Richard Hughes » November 30th, 2004, 3:51 am
Lab-created rubies are more properly known as synthetics. These are man-made rubies that have exactly the same composition and crystal structure as the natural mineral. Thus they will have the same properties, including hardness, density, refractive index, etc.
In the case of synthetic corundum (corundum is the mineral; ruby and sapphire are color varieties of corundum), it can be produced by a variety of methods, such as Verneuil, Czochralski, hydrothermal, flux, etc.). The first two processes are extremely efficient and huge stones costing just pennies per carat can be grown. The latter two processes are much slower and less efficient and such stones cost $50-200 per carat. Identification depends on the growth process. For the most part, it involves a skilled gemologist examining the inclusions visible with the microscope. It is not a job for an amateur. A full gemological examination should also involve determination of whether or not a stone is assembled, as well as the presence or absence of treatments and the types of those treatments. Richard W. Hughes |
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Hello,
For sure hardness is the same for lab created rubies and sapphires than their natural counterparts: 9! But there is 9 and 9... I mean, the hardness is depending as the RI of the chemical composition and the way the atoms arrange with each other. For example a ruby will be slightly less hard than a blue sapphire which will also be a little bit less hard than a star blue sapphire... But we are speaking here about tiny differences that are not easy to measure. I was told that some Mogok cutters with a lot of experience know when they put the stone on the wheel if it is a ruby or a blue sapphire... Legend? May be not! On the second question, it is easy and not easy: There are many test you can use to make the difference between natural and synthetics rubies and sapphires. Some are diagnostic, some are just indicative... The key is knowledge for sure but the most important is to my opinion experience. You can learn by heart the excellent "ruby and sapphire" from Richard Hugues as I did before to become gemologist... this book was my bible for 2 years before me to decide to become gemologist... But when you are in front of a stone in a market or a lab. To know what to search for is most of the time not enought: You have also to know how to find the evidences to be able to make your decision. This requires that you had the possibility to study at least once in your life all these stones either natural or synthetic and be able to compare them. I will tell you about my own experience on this subject: When I was studying in Burma they had very few synthetics, so after graduation I had more questions than answers. I had Richard Hugues book and I was trying to find in any gems what he was describing... I was reading and reading again affraid to miss something. In order to learn more I went to study at GIA. I was then very diseapointed on this point as GIA does not go to details about synthetics. For them there is flux, flame fusion and natural stones. What about Kashan, Chatham, Douros, Ramaura, russian hydrotermals? No origin for the natural gems or the synthetics, no hydrothermal synthetics, very basics about treatments... I had 2 gemology diploma and still was unable to be sure that I had seen once in my life one of these synthetics I was reading and reading about! Damn... Finally I joined AIGS and I was then able to study all these gems as they have an excellent and complete collection of such natural and synthetic corundums and emeralds treated or not. AIGS have a course specialised on synthetics and treatments (that I''m now currently teaching regularly in Bangkok. For more details, visit the following link: Synthetic and treatment identification at AIGS Bangkok ) It will be if you join 1 month of intensive work on these damn stones. During this month you will be able to study around 1000 gemstones and get an idea about what is it about... But dont dream either this course will not make you a an expert as in many case the correct identification will be only possible using some advanced gemological equipments that are too costly for the "jeweller gemologist" and that are found only in gemological labs (Here again for more info you can visit the following page: AIGS laboratory instruments ) Hoping to have helped you, All the best, |
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Thanx Mogok & Richard M,
Its really pleasure to read about gems. but still, But today i am doing tradings on gems as per knowedge on hardness test , specific gravity test ,magnifiers and others .... But not the least by touching the stones we can know whether that stone is synthetic or natural. Dear mogok & Richard M,as per your knowledge also by touching the stones you can come to know whether that stone is natural or synthetic? In future in will be looking for some gemological courses too. cguy |
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In one word: "No" Sorry, if it was possible labs would not spend tens of thousands of dollars to buy machines like spectroscopes,... and whatever the hardness test is a destructive test to it is not advised to use it (except on your own stones if you want...) All the best, |
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Hello Mogok,
Yea I agree with you, but in market the strategy is almost like this only. Even master jewellers do the same thing . If i am not mistaken, people dont want to spend much more money on gemology course instead they want to learn about books and get practical. am i right? Most people do !!!!!!!!!!!!!!!!!! cguy |
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Chatam emerald crystals... from HERE
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... but, there is more to the story. The more inclusions in a lab crystal, the less natural they look! So I am not sure how lucky you need to get to obtain an emerald with an entire "garden" that looks like the real deal. Some lab grown crystals are strangely true to nature, but their inclusions are still the tell tale marks of origin.
Just one note to consider. Any such technicalities get superfluous, I would think, unless you are going to walk your jewelry at every gemology club in town  It is that much easier to trick common sense than intricate lab tests.If you wih, Mogok's warning reads two ways: "do not trust shoddy gem IDs" and "no expert can tell every fake from every natural off the bat" ! |
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One of the gem nuts i know said something the other day that was intersting:
When I was poor everyone assumed that my nicer gems were man made. They were usualy wrong. Now that I have money everyone assumes that all my gems are natural. They are usualy wrong. He buys by looks and pays the right price for the class of stone it is. What class its in doesnt matter much beyond the amount of money it takes to take it home to him. I agree with him. Arent kewl looking gems what its all about? Buy th stone not the paper. The paper just detrmins the cost of entry. |
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Hello Ana, Coolguynamek and others,
You have read me right: Several exemples from my experience: While I was studying in Burma my classmates from Mogok had already 20 years experience in the gem mining and the trade. They were able to recognise most stone using their eyes... without to be gemologist! I was feeling so "zero". Now take the best laboratory gemologist and send him to Pailin gem market and give him 3 good quality stones (unheated heated and a synthetic): Ask him which is what when he is without his instruments in the same conditions as a local cutter: He might have some serious problems to conclude... Now take the burmese guy so good in Burma and put him in the same conditions as the lab gemologist in Pailin. He will also be in serious trouble as he is experienced only on burmese gems... and Pailin gems will looks unreal for him. Send a good synthetic to local cutters in Pailin or Mogok, or bring them a stone from an other mining area, they will be confused, they will look at it at will say: "This is not a stone" it means that they dont recognise the stuff they are usually working with. These people most of the time will recognise that the stone is not from their place but will not be able to decide weather the gem is natural, synthetic... They use a personal mix of feelings and logic. They use unconcious knowledge... something you can call experience. A trained gemologist is given the knowledge about gems and gem identification to be able to identify correctly any stones with a minimum of instruments. They are teached about techniques that are useful and applicable to do the things correctly. Coolguynamek, think about: If the hardness test was one of these it would be teached in all gemology course... Now, you can train yourself to identify rubies by their hardness, I dont think that you will get any positive results and if you do it will be after so many mistakes that your reputation will be destroyed before you to become efficient. This identification technique will probably send you to bankrupt... So just be realistic and professional: it is cheaper to spend some money in learning how to act professionaly, it will avoid you many expensive mistakes! Taking a gemology course is an investment for sure. It cost money and time, thats right! But you gain skills as you will have some experienced teachers with you to show you what is correct and what is not. You will see the stones with your eyes, study them with your book near you... If you dont do, then one day you will make some mistakes and may be in one deal loose 5 times more money than the cost of the gemology course... To learn what? To learn that you might have gone to put some money in upgrading correctly your skills. Being unprofessional is fine when you are a hobbyist, no problem... When you want to live from your skills, it is different story. But dont take me wrong, very few gem dealers are actually gemologists. You can be active in the gem business and do very well. Most buyers have knowledge in gem cutting, but getting also some gemological knowledge is a wise investment. It is a plus for all professions in the gem trade but many people can live without studying it. I believe that if they did they would probably not have lost their money and time... Studying gemology will teach you the simple techniques that will help you to identify most gems. But of course everybody has limits even the best gemologist and there is all the time apoint where the best expert will have to say that in the given time with the instruments at his disposition he cannot conclude. This was for me one very good indication that I had a good gemologist in front of me. A good gemologist is a guy who know where he dont know anymore... Just think about that Coolguynamek... All the best, |
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If you are serious about studying gemology, the synthetics/treatments class at AIGS is one of the best, and with an expert teacher like Vincent, you can''t go wrong. Their stone collection in that area is second-to-none. When I designed that class back in the 1980s, I did so with the idea that it was not enough to see four or five specimens of each type of stone. You had to see dozens. And so we assembled parcels of Verneuil synthetics, parcels of flux synthetics, parcels of cooked Ceylon sapphires, parcels of Burma rubies, parcels of Thai/Cambodian rubies, etc.
To the best of my knowledge, this approach has not been reproduced at any other gemological school in the world. It really gives you a chance to learn a lot in a brief period. I believe there are entrance requirements. Check with Vincent for details. Richard W. Hughes |
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Dear Mogok & Richard M, Its really true that without the knowledge of gemology training a person can''t move forward and buy/sell gems. One has to get himself/herself into confidence and do the course for the same. But I cant understand about the master jewellers who has not dont any gemological course and can identify the gems whether it is synthetic & natural. Do we have to trust these jewellers who are masters or are they telling the truth to the person who wants to sell there gems and jewellery. coz nowadays so many synthtic stones are on sale. coolguy |
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Why would someone who knows tell what he knows is yet another story. I a very convinced that a serious amount of visual experience (years of it!) at least compensate for the science in the complicated overlapping way that Vincent explains so very well... "Experts are just as good as the sum total of what they have seen"  You can trust these experts only if you know at least as much as they. A lab report is much easier to trust with some basic understanding of science. Unlike extensive hands on experience with gems, basic science is cheap and readily available, imo. Just compare the cost of a second hand college book with the cost of any fine gem!  ... just couldn't stay away from this thread. |