"Heat Treatment of ruby-sapphire course made me a real eye-opener to look at new opportunites in the precious gemstone industry", A.G., Sri Lanka (June 2016)

"As a gemologist, I came with an expectation to understand treatment detection, but I left with a load of knowledge of things I was not aware. It has been a great experience. B.M., India (Junre, 2016)

"This class is fantastic! I am very happy. Ted is generous beyond belief in sharing his knowledge. Thank you, thank you, thank you." K.G., USA (June 2016)

"Thank you Ted!! These were the most informative 6 days pf my gemological journey till date. The best first-hand knowledge “pure knowledge” has provided by Mr.Ted Themelis has opened new horizons fr us (the wanna-be gemologists). Lessons larnt: Keep experimenting, keep learning, keep exploring, keep heating! Ted, you are amazing.. you rock ..!!" Y.S., India (May 2015)

"Dear Ted, First and foremost, thank you. As a result of this course, despite any disappointments in regard to my expectations on the potentialities of my stones, I no longer “walk” along blind. I’ve been able to learn and at the same time make important connections through this course. I am grateful too I’va been able t meet such as you with your level of integrity, which is rare today. In summation, thank you." O.M.,Australia (May 2015)

"Good structure of the H/T course... fun… profitable… many new ideas." G.M. Thailand (May 2015)

" Amazing course.. for sure the best gemological course that I have taken. Good mix between practical and advance theoretical information. Thanks for all.". E.S., Switzerland (May 2015)

"Ted, I had memories that will last forever. I wish to learn and share experiences down the road. Thank you for all the things you shared to us in a short period of time.." H.W., Burma (May 2015)

"Great course! Practical, dynamic knowledge, maybe the most valuble information in Ruby & Sapphire field; samples like encyclopedia! some even disappear in market for decades; that 's wonderful.. wish to learn more!" - B.Y.China (March 2015)

"Very compehensive course, updating information and knowledge used to be be taken for granted.. Heating practice is amazing, which is hard to have access to elsewhere.. more dyas would be even better" Y.Y, China

"Thank you for a great course; you never got tired for answering all our numeorus questions.." N.A., India

'Hi Ted. This has been the only course that I could "cook" ruby & Sapphire! and it is cool to see so many specimens. I will remember what you said: the first 10 years are the most diffiuclt.. i will survive this..!" J.S. China

"The knowledge provided in this course is as rare and valuable as these gems are. I wish I would have doone this course 10 years ago; also very much impressed by Ted's teaching style" S.M. Pakistan (Oct.2014)

"This course was really informative and presented in an excellent way. I learned so much by doing this course. Had an awesome time!". A.L., Kong Kong, (Oct.2014)

" More than I expected" - M.C. China (Oct. 2014)

"Inspiring and discovering in a great company". M.H. Poland (Oct.2014)

"Fantastic experience - incredibly informative mix of science and "alchemy". Thanks Mr.Ted you've opened my eyes again to the tricks of the trade - buyer be aware in amazing Thailand" -S.A. UK (May 2014)

"Very informative- great hands-on, very nice to see and participate in the process and to see and examine the examples" - T.G., USA (May 2014)

"Great start - need two more weeks" - B.D. USA (May 2014)

"Very good insight into a very very vast field of heat treatment which itself is a state of flux". -P.J. Tanzania (May 2014)

"Not only for gemstone treaters but also for gemologists, the course is a very valuable source of information and practical knowhow. The combination of theory, applied treatment and microscopic observations provides a deeper knowledge of the subject: Treated or not treated." Dr. W.E., Bern, Switzerland (Jan.2014)

"The knowledge I gained after the course will definetely change my life. This knowledge will convert into money and will minimize my waste in the near future. Thank you very much, I am sure the amount we paid you was very small, but the knowledge is millions of dollars." - N.T., Jakarta, Indonesia (Sept.2013)

"Thank you Mr.Ted Themelis, the name of my father. After the course, I improved a lot for treating gems.. Thank you very much for teaching me.. Best regards." Dr.R.P.,Cambodia, (Sept.2013)

"The training is very very useful which I received by one of the most experienced and qualified trainer in the world. But I felt training should have to be done at the basic (at least) knowledge including the language to catch the meanings right away. I felt lucky to grab this opportunity. Many many thanks to the lab associates. Key expressions: very very useful, wonderful." G.P. Katmandu, Nepal (Sept. 2013)

"Feelings about the course.
Theoretical: good presentations and explanations. Even if the student doesn't understand the teacher has the time to explain more or 2 times.. until the student gets a better understanding, that's very good..
Practical: we were directly involved in the preparation of chemicals of the process also and during the practical exercises. The teacher was providing good explanations to help us to understand and to practice what we have done in the theoretical sessions.
Conclusion: The combination between the theory and the practical was well coordinated and the atmosphere during the course was friendly; we were feeling very comfortable.", I.M., Madagascar (Sept.2013)

“A crash course in staying afloat in a sinking economy – The Aftershock Investor”, D.Y.M.K., Singapore (December 2012)

“A bird’s eye new info into the labyrinth world or gem treatments.” R.K., New York, USA (December 2012)

“A very informative course that opened a plethora of gemstone treatments-techniques and processes. One of the best decision of my career in jewelry and gemstones to attend this course. Thanks for having a nd providing such an excellent complication and knowledge to jewelers.” S.J., Bangkok, Thailand (December 2012)

“ I have learnt so many thinks which I didn’t know, even about ruby, sapphire and geudas. And also appreciate your treats as well (pepsi, coffee, sweets, etc.). This is the best course -you tried to teach best to us. Thank you Ted and also Anne.” T.D., Sri Lanka (December 2012)

“Actually from this course we got to know lot of knowledge. Got to know about blue sapphires, rubies and more. The course is perfect.” S.A., Sri Lanka (December 2012)

“Thank you very much for your courses; it was FANTASTIC” --S.T., France (September 2012)

“I am really thankful to you for sharing your experience and knowledge with us in a very short time. I have really learnt a lot of things..” - K.S., India (September 2012)

"I want to thank you for The Course #510: Ruby-Sapphire Treatments. I can say that I have already started to see that it is really beneficial for me. It has increased my self-confidence and awareness in the jewellery business. Thank you really very much for your efforts and teachings" -H.Y., Turkey (September 2012)

"The course was well-placed therefore I was able to grasp most of the stuff taught, when didn't understand I was able to ask Ted. Therefore, overall I had a really good experienced here." -- M.N., Sri Lanka (April 2012)

"The course for heating ruby & sapphire from Gemlab is likely open many windows and doors of my mind regarding the chemistry of chemstones and the methodology of gem treating. It is like the first step of the field of gem treatment. Thanks." -R.A., India (March 2012)

"The course helped to clear all myths regarding heated gemstones. and enloghtened my knowledge and to know more about gems. Thanks to Ted Themelis" - Z.S., India (March 2012)

"The course was excellent. Only the duration of the course should have been longer. And some more information on treatments od semiprecious stones everthing else was perfect. Thank you Ted" - A.S., India (March 2012)

"I learned a lot from this course. My knowledge on treating ruby-sapphire is widen. Lectures, presentations an practices are very informative. I will apply the gathered knowledge from this course in practicing treatments in the future" - S.A. (Sri Lanka (June 2011)

"Very exciting five days , where I could obtain unexpected knowledge about gem treatments in detail"
-B.A., Sri Lanka, (June 2011)

"Well-noted your kind explanation concerning the treating ruby-sapphire. Thank you very much for the good teaching. Everything are OK. In my side, I wanted to know more about heat-treating in detail practically. I would recommend to other Korean people this class." - Y.K.A., S. Korea (June 2011)

"Very, very, very interesting class. You take time to explain us until we understand, As far as I am concerned I need more scientific background to really understand everything. But thanks to your practical approach and your patience I can say that I've understood 95% of your course. Next time I hope to see more stones with a little explanation on the side which tell us what we need to see and the stone. Thank you very muck it is a wonderful class and a wonderful experience. You are the best teacher.." -M.A., France (June 2011)

"Experience was wonderful. Now I understand how little I know about ruby-sapphire. I will come back to learn more about rubies-sapphires. Thank you Mr.Ted", - J.G. (June 2011)

"An invaluable course for all gemstone dealers" - R.H., Australia (Feb. 2011)

"A comprehensive A-to-Z gem treatment and how to!" - E.C., Kashmir (Feb. 2011)

"It was a rigorous an enjoyable course of which gave me insight to the treated gems -part of the gem trade" -M.H.K., Pakistan (Feb. 2011)

"Intense and/but thorough give you reasons to see things from a new point of view" - A.L., Greece (Feb. 2011)

"An intense course giving proper knowledge and skills to any dealer to make better steps and make proper decisions" -C.C., Italy (Feb.2011)

"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-hobbies 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)