Saturday, November 06, 2010
An update on the heat treatment of ruby and sapphire
Gem-A, 27 Greville Street (Saffron Hill entrance), London EC1N 8TN - United Kingdom
We are extremely fortunate that Ted Themelis, who has had first-hand experience in the treatment of ruby and sapphire, is able to visit the UK to present this important seminar.
The seminar will be held from 10:00 am to 5:00 pm, with an hour's break for lunch. The day is to be divided into eight sessions and, as you will see from the following programme, you will learn not only about the treatments used to enhance these gems, but also about their pricing structure. In addition, between each session you will have the opportunity to examine the treated stones for yourself, so please be sure to bring along a penlight and your 10x lens. Further details of the programme for the day are given below.
Ted Themelis graduated with a BSc from the City University of New York in 1975. He has worked extensively in development, engineering and manufacturing of innovative gemmological testing instruments and apparatuses. Since 1979 he has been involved in various experimental gemstone enhancement projects, primarily in the heat treatment of ruby/sapphire.
Ted has travelled extensively, to the most inaccessible gem mining areas and has published over 120 articles on gem-related subjects. He maintains state-of-the-art gemstone enhancement laboratories in Europe, Thailand and in the USA, providing heat treatment technology, equipment, and services to the gem and jewellery industry. In his workshop in Bangkok he fabricates special gemmological LED microscopes.
Seminar fee: £125.00. Gem-A members and registered Gem-A students: £98.50.
Click here to download a booking form.
Programme
Session 1: Diffusion and Heat Treatment of Ruby and Sapphire
Characterization of diffusion (old and new interpretations); type of diffusion in ruby and sapphire; gas diffusion, impurity diffusion; model of diffusion mechanism in ruby and sapphire; diffusion in untreated, natural ruby and sapphire; surface, subsurface colour and impurity diffusion in ruby and sapphire; comparison and conclusions of diffusion-treated rubies-sapphires.
Session 2: Revisiting Beryllium-treated Ruby and Sapphire
Review of the first generation beryllium process; new developments of the second generation beryllium process — Be-treated blue, yellow, greenish sapphires; identification of the Be-treated ruby and sapphire using classic gemmological instruments; detection of beryllium in ruby and sapphire using LIBS, LA-ICP-MS and SIMS.
Session 3: Classification of the Heat Treatment Process of Ruby and Sapphire
Additives — gas, solid and mixtures; heat treatment processes of ruby and sapphire classified into three major groups; methodology of the practical, commercial heat treatment processes; models of the heating processes of ruby and sapphire.
Session 4: ‘Romancing the Geuda.’
A documentary film on the heating of geuda sapphires, filmed by Ted Themelis in Sri Lanka in 1986.
Session 5: An update on the fracture-filling processes
Nature and classification of the fractures in ruby and sapphire; methodology and applications of the borax-filling and lead-filling processes; combination fracture-filling processes (borax-silica-lead, etc.); desolvation process; comparison features between borax-filled and lead-filled rubies; fracture-filled rubies — features, characteristics, identification, stability.
Session 6: Value of the Heat-Treated Ruby and Sapphire
Pricing structure — a journey from the mines to the consumer; model of mining production and value of ruby and sapphire; cost effectiveness index of the heat-treated ruby and sapphire; value of the heat-treated ruby and sapphire.
Session 7: Conclusions
Considerations on the definition of a ‘gem’, ‘treated gem’; examining the character of a ‘gem’; treated vs. enhanced gem; concluding thoughts and recommendations for gemmologists.
Session 8: Surprise!
Results on the ongoing experimentation in heat-treating new types of ruby and sapphire.