Creating Rubies with Chemistry – Interview with EUCYS 2016 Winners

Feb 9, 2017

The winners of the 2016 European Union Contest for Young Scientists (EUCYS) EuChemS Award are three young students from Germany led by their commitment and passion for chemistry – Christian Schärf, Paul Rathke, and Friedrich Wanierke.

Their research project, “Alpha-aluminium oxide-based gemstones: Development of a chemical synthesis process prompted by current mining conditions”, started from their interest in gemstones, but soon they realised there were also some positive social outcomes of creating gemstones in laboratories.

EuChemS –  First of all, thank you for your time, and congratulations for winning the EUCYS EuChemS Award. Could you tell us more about how did your winning project begin?
Christian Schärf, Paul Rathke, and Friedrich Wanierke
(CPF) –it all started when we read in a newspaper that a ruby, the Sunrise ruby, had been sold for about 30 million dollars. When you ask people what is the most expensive gemstone, they will most probably answer “diamonds”, but in fact rubies are more expensive when they exceed a certain weight. Many people have a fascination for gemstones, a fascination shared with chemists, and previously with alchemists, who have always tried to synthesise gemstones, so we thought that creating rubies in a laboratory would be a really interesting challenge. We have also evaluated the socio-economic and political impact of gemstone mining in developing countries and learned about some of its terrible consequences on the environment and the lives of mining workers and this gave us extra motivation to embrace this research topic. Finally, our chemistry teacher is specialised in crystals, so we knew we would have good support in this topic.

So how did you approach this challenge of creating laboratory gemstones?
– Our starting point was to first look into many publications to learn and evaluate which methods already existed and to find an optimal method. Actually, synthesizing rubies is already possible since the XIX century and in 1902 French chemist Verneuil invented a process that set the industrial standard in this field. The problem was that his solution is energy expensive as you needed to melt raw materials at a temperature of 2000º Celsius and a seed crystal is required. Our goal was to create gemstones at a significantly lower temperature and without the use of a seed crystal.  

Rubies, as well as other gemstones, are a variation of aluminium oxide, which is not expensive and has been used to chemically synthesise rubies for more than 100 years. If we make a price comparison, a  5,1 g ruby is worth the same as 30 000 train wagons full of aluminium oxide. In order to get rubies, the only change you have to make to the aluminium oxide is to replace some of the aluminium cations by chromium cations, a process which is called doping. The chromium ions must be randomly distributed over the whole crystal, and to randomly distribute them we must go through some kind of a liquid phase during the synthesis process, something normally done at 2045º Celsius. Finding a chemical solution which did not need such a high energy-demanding process was the “magic” of our project.

EuChemS – How did you get to a ruby at a lower temperature?
– We first wanted to synthesise powder before we started with macroscopic crystals, so we decided to use aluminium nitrate and chromium nitrate instead of the oxides, since they contain the needed cations and are water soluble, thus providing the liquid phase. Furthermore, we added citric acid and ethylene glycol. When we then heated the batch and evaporated the water, a networking structure in which the cations are integrated has formed. After we obtained this structure, we gradually broke it down at 450 °C to get an amorphous mixed phase consisting of chromium oxide and aluminium oxide. At this point, the chemical composition of our batch is the same as a ruby, but the structure is still different. We managed to obtain the desired alpha aluminium oxide structure, and therefore ruby crystals, by heating the batch to 1100º Celsius.

EuChemS – And what made you think on how to lower temperature?
– We were inspired by the same principle used when you have icy roads and you put salt on them –the melting temperature decreases. In this case, we did the same, but not for water but for aluminium oxide. Instead of salt we used a compound named cryolite (potassium aluminium fluoride). This way, we managed to obtain single ruby crystals, hexagonal plates, which is the expected crystal structure, with diameter of 0.2 mm and height of 0.2 micrometres.

EuChemS – When you look at it, is this synthesis ruby crystals any different from an actual ruby?
– Actually, you cannot recognise them with your eyes due to the small size of the crystals, but when looking at sequence electron microscopy images you can clearly see that we have formed crystals with regular hexagonal shapes, which you can expect when you see a natural ruby crystal structure. We also proved through x-ray diffraction that these crystals have exactly the same structure as natural rubies.

EuChemS – That is absolutely amazing!
CPF – …indeed, we thought the same when we saw it. Moreover, this approach allows the production not only of rubies but also other gemstones, by introducing other elements into the aluminium oxide structure. We haven´t explored these possibilities but, for example, when you take iron and titanium at a certain ratio, the structure turns blue and we have a sapphire.

EuChemS – When can we then expect big gemstones produced by this process?
There are still many issues to be solved, as porcelain reacts with fluoride, meaning that the fluoride based cryolite partially dissolves porcelain and when solidifying the crystals would be stuck to the crucible. We have conducted some research on this but we are unfortunately missing ovens to proceed with this endeavour. When we first started the project, participating at the national competition was our main objective. We have already gone much further that we had originally planned.

EuChemS- Are you still working on this together? Are you at the same university?
Unfortunately we are now studying at different universities and different countries so our research on this topic in not really advancing. Nevertheless, we will try to advance on this project during our vacation time prior to our participation at the International Science and Engineering Fair (ISEF) 2017.

EuChemS – Did you publish the findings of this project?
No, we didn´t publish, there was a suggestion to publish it but we didn´t do it yet, maybe after ISEF 2017 competition when we have more complete results.

EuChemS – What is the applications of this research on our everyday lives?
Due its extraordinary strength, rubies do have many technical applications, namely in lasers used in industry, medicine, or in regular laser-pointers. They are also used in classic arm watches, something which is not used much anymore, but you should probably have ruby in your pocket right now as your smartphone´s camera will most probably have a ruby coating. This coating avoids scratches, and your photos do not get red as this coating is super thin and probably has a very low percentage of chromium, thus giving it a very subtle intensity of red. Other than these applications, there would be other kind of impacts as this technology would also have a positive environmental impact in mining regions where workers and environmental protection regulations are too feeble.

EuChemS – Have you thought about applying for a commercial patent?
CPF – Not really, right now what we really want is to focus on our university studies.

EuChemS – What are you currently studying, chemistry?
Paul Rathke – I am studying chemistry
Christian Schärf – me too.
Friedrich Wanierke – I am studying materials sciences, which is 50% chemistry and 50% physics.

EuChemS – Did you have support from your teachers?
– Yes, but not only. The list of supporters is long and they are very dear to us, namely our chemistry teacher at the Albert-Schweitzer-Gymnasium Erfurt who got us the connections, Mrs Purgahn , and our mentor in Leipzig Prof. Krautscheid and Stefan Dietrich, a member of his research group, as most of our research was done at the facilities of the University of Leipzig. We also had a lot of support from STIFT, a foundation from our region which is dedicated to supporting students from our region going to the national competition, and finally from our national organiser Jugend forscht.

EuChemS  – Did the initiative to compete come from you? How did you learn about this competition?
– We started our project before knowing we would participate in competitions but we were so proud of our achievements that we wanted to compete, and it is very common for a lot of science projects in our school to participate in those competitions, so we already had a structure in place.  So we first went to the regional level, then state level, then national level, and we were lucky enough to be part of EUCYS, it was an awesome experience. We were quite enthusiastic, as after each round we would have extra support and training, for instance in presentation skills, on how to better articulate our ideas and how to do it in English.

EuChemS  – How were you put in contact with the Leipzig University laboratory?
It all started with our chemistry teacher that knew very well a professor at the Leipzig University, so we had the opportunity to go there to get training and to discuss our project. They were kind enough to support us through all the experiments, so we would do the experiments in Leipzig, evaluated the results mostly at home, coordinated the next steps and came back to the lab for further experiments. As we continued to go further in the competition we had opportunities to meet more professors from various academic institutions. At the current stage there are three universities involved, the University of Leipzip, the University of Würzburg, and the University of Darmstadt, with which we were put in contact through the German Research Foundation. Leipzig is where we started and where we have done most of the research for our project. It also there we got an introduction on various analytical methods, and then it was great to analyse things by ourselves, as such methods are not taught at highschool.

EuChemS – I can imagine that this is way more advanced than what you normally learn at school…
– Yes, by far.

EuChemS – When did you start having interest in chemistry?
Paul Rathke – I was initially more interested in computers, but then I quickly discovered chemistry and everything changed.
Christian Schärf – For me it was the same, I was first more interested in mathematics and biology but then I settled for chemistry.
Friedrich Wanierke – I have been interested in sciences in general since an early age, but my particular interest for chemistry started when I switched school at 14.
CPF – There are many ways in which you can encounter chemistry in school, and its understanding requires some time and effort. Many people hate it and only some people love it as it takes some time to realise the interest and beauty of it.

EuChemS – Were your friends and colleagues supportive of your project, or did they look at you as aliens for spending so much time at the lab?
That´s a very interesting question, actually our school has a special focus on natural sciences and computer sciences and restricts entrance via exams, so everybody on our school is already sort of keen on sciences, and it is not rare for students to participate in science competitions, so our research “hobby” was seen as natural. However, when talking about our project to many of our friends outside school and they would say something like “I really don´t understand what are you talking about”. Then, when telling them that we were going to the national level and the European level they would say “what is wrong about you?”.

EuChemS –Is there any message you would like to leave to younger people who might be reading this interview?
– They should be aware that the chemistry which is shown and taught in school is just a very small subset of the chemistry you would study at university, due to the budget and laboratory rooms limitations at school. They should be aware that chemistry is generally much cooler than what you do at school. This project also taught us that if you want to be successful you have to always go further, to do more than everybody else and don´t procrastinate. Moreover, if you are going to science competitions, it is essential to get good supporters and to never underestimate yourself, it is very important to be confident and to know how to show the real value of your project.

EuChemS – Finally, we would like to wish you great success with the continuation of your research in chemistry.
Thank you, and we would like to thank EuChemS for this prize recognising our research!