"The course was extremely informative in a little known field and the 46 hours of lectures and three lab firings were particularly valuable as both an academic and hands-on practical training. In addition to the course the very many discussions with Ted revealed a great wealth of information from Ted's many years of practical experience in the field of heat treating gemstones... As one of Ted's students I am delighted to bring away from the course a full set of lecture notes by Ted, my own lecture notes, lab reports, two books by Ted still in print (some are sold out), and some of my own sapphire samples now much improved by the beryllium process." -Dr. M.J.R., Saudi Arabia (Jan. 2006)

"The heat treatment course, and its comprehensive syllabus, is unique in the world, as is course-creator and instructor Ted Themelis. The course is a (highly) beneficial natural progression for the gemologist, but is also appropriate for the gem-hobbiest with at least a minimal background in science. Either way I highly recommend the course." W.H., USA (Jan.2006)

"The course of Ted Themelis is a must for everybody who is dealing or handling rubies and/or sapphires. You learn in detail with the support of experiments what is possible with rough material, which kind of treatments are in use and what is going on in the marked." -Dr.A.R, Swarovski, Austria(Sept. 2005 class)

"I would like to send my respect, salute and compliments to my teacher & confident Ted Themelis. I am exceedingly grateful to you for the marvelous and truly amazing course with such intensity that took us from an in-depth theory to the practical work through Ted's unique teaching method that even a 3 years old baby would catch up with." -V.P., UK (June 2005 class)

"The course gave me a good insite to the history, theory and mechanics of heat treatment and demonstrated the capabilities, as well as the limitations, of heat treatment for enhancing the beauty of rubies and sapphires." - Dr.T.P., Australia (May 2005)

"Ted Themelis' course opened for me a new dimension of understanding the heating processes of ruby-sapphire. Myself, being far away from gem business, could grasp so much in such short time. It is really an amazing experience. S.S., India (Jan. 2005)

"This course is very useful for me as gemologist and I got more gain and information. I am very happy that attended the course ad I hope you will make some more courses like this. Thanks for the help and giving me more knowledge." S.P, Singapore (Dec. 2004)

"I found that the short 5-day course has enriched my knowledge an opened a new horizon in how to see treatment from all different aspects and possibilities". - M.P. Indonesia (Dec. 2004)

"An eye-opener of corundum heat-treatments. Learnt more in 5 days than 5 months I tried researching heat-treatment, as all my In case an doubts wee answered instantly". -S.P., Indonesia (Dec.2004)

"Before taking the course, I was in a Catch -22 situation, to start or not to start the heat treatment of gems. But now I know for sure." -S.K., India ( Sept 2004)

"I came here to learn how to treat. But now after a week I learn not only treatment, the whole aspect of business involved. What I learn in a week is worth 20 years of experience. Thank you for everything." M.T.H, USA (Sept 2004)

"This is definitely a good course for me. When we started, I had no idea about how to heat the stone at all. Now I know the furnace, the process and the magic of science behind it. Well for this, I have to thank Mr. Ted and Mr. Angelo.. They were real professional. Thank you. T.P., Thailand ( Sept. 2004)

"The course was a very intensive and comprehensive learning about corundum and heat-treatment. Mr.Ted Themelis gave us all of his experiences and knowledge which he gained from his energetic activities in Asia for a long period of time.  By participating the course, we came to understand a lot firsthand knowledge about corundum and treatments of corundum which are very much essential in identification of ruby and sapphire. Thank you, Ted, and all the best to you!" -SKK & SKB Korea (June 2004)

" Our goal and why we took this course, is to achieve the knowledge to treat our 50 kg ruby rough & our 75 kg Umba sapphire rough. Ted has opened us a new point of view in the stone business & a new path in the treatments and how we are supposed to accept them. Thanks for sharing with us all your investigation done trough lots of years. -A & M. C, Spain (June 2004) 

"Your class was one of the most interesting and informative classes that I can remember. You really know your stuff. I love to here of your adventures, commentaries and your ideas. I also appreciate your straight forward approach and honest thinking." -T.C., USA (May 2004)

"Thank you for discussing everything for us. I enjoyed the class very much.".- GS., China (May 2004)

"I really enjoyed your class and I learned even more than I hoped to.  Nothing was a disappointment for me, on the contrary I would have really liked to stay longer and learned more.  It was a great class for me and you were correct in your thinking that we would see treatments in a different way from now on.  At least I do!  I really enjoyed it, I think you have put together a really good class and presented it well.  I consider you a great teacher and mentor. " - W.D, USA (May 2004)

"The course helped to understand the process of heat treatment to get the correct material for treatment, to build and operate and maintain the furnace." -R.D. India (March 2004)

"The course gave me an overview on what causes the corundum to change in color and clarity and how we could manipulate various parameters o achieve best possible results. It also taught me what are the additives used, why are used an what the additives do to improve the characteristics of the stone. I also got to learn the different types of furnaces and their advantages for the various applications." -A.S. Tanzania (March 2004)

"The course started from the theory of diffusion and extended to actual practical implementation , methods of heat treatment , necessary equipment for processing. The course is conducted by master of the heat treatment field, highly recommended for learning heat treatment. Ted is the field marshal in the gem heat treatment field; if someone wants to succeed, he must attend the course". Dr. L.R., Taiwan (Jan. 2004)

"After taking your course I changed my idea to buy and sell gemstones. The course gave me a new view. We had trained with a very high tech furnace." N.J., India (Sept. 2003)

" I thoroughly enjoyed the course that I attended, and was wondering if Ted had any more courses that would complement that highly informative course. I want to relocate to Thailand and procure quality gems for the contacts that I have here at this moment in time. Ted's course was an eye-opener for me, hence enthusiasm to learn more." -D.W. UK (Sept. 2003)

"Ted Themelis' course in Heat Treatment enabled me to learn first hand about all of the different ways in which gemstones can be heat treated, together with practical demonstrations... it was refreshing to be able to take a course which discussed all of the different methods openly". -Dr. R.C., Australia (September 2003)

"The course gave me a very good idea of how the process of heating rubies and sapphires works. I want to become a gemologist and I will definitely benefit from the experience of seeing first hand how the machine works and the effects of heating treatments on rubies and sapphires. Your course enriched and clarified enormously my understanding of what I had previously read about stone heat treatments. Your course gave me the chance to see first-hand how the heating process takes place and its effects on stones. Therefore it was a very valuable experience not only form the theoretical point of view but also from the experimental side. It is amazing how much I could learn in just one week. I am very grateful." L.T., Italy (September 2003)

"Ted Themelis' course in Heat Treatment enabled me to learn first hand about all of the different ways in which gemstones can be heat treated, together with practical demonstrations, or at least photographs, of most of the traditional and modern methods. It enabled me to make appropriate decisions concerning the most applicable and cost effective heat treatment methods to utilize for our company heat treatment operations in Bangkok (the treatment of African rubies and Australian blue sapphires). Normally heat treatment methods and formulas are held as a closely guarded secret, particularly highly controversial ones (such as the beryllium diffusion heat treatment), so it was refreshing to be able to take a course which discussed all of the different methods openly". Dr. R.C., Australia (Sept. 2003)

"I found Ted's Heat Treatment course to be informative and interesting, particularly in the areas of process and furnace design.  The means to calculate appropriate heat treatment parameters in terms of heat-up, dwell and cool-down were particularly informative. I would expect to use knowledge gained from this course for the implementation of large-scale heat treatment of mine-run Australian sapphire in the future." Dr.S.P., Australia (Sept 2003)

"I am writing to thank you again for one of the best educational experiences of my life. I understand more and more each day the training we received, I plan to ensure that you have NO regret for the time you spent in preparing the class and sharing your experience with us." -JCE., USA (July 2003)