Ted (Theodore) Themelis was born in Lefkada Ionian island, Greece. He earned his B.Sc. from the City University of New York in 1975. A self-made entrepreneur with a career spanning over four decades, starting in 1979 designing and fabricating innovative microscopes, spectroscopes, and other gemological instruments, many of which are still in use today. Ted’s expertise in the heat treatment of ruby-sapphire is widely acknowledged. In 1992, he published his first book, “The Heat Treatment of Ruby & Sapphire,” and has since released two updated editions (2010, 2018) and seven monographs (2024). In 1997, Ted embarked on a significant geological-gemological field research project on Burmese gems. This extensive study resulted in the publication of two volumes: “Mogok-Valley of Rubies & Sapphires” in 2000 and “Gems & Mines of Mogok (Burma)” in 2010. These volumes are the only comprehensive books dedicated to Mogok (Burma) at that time. From 1984 to 1986, Ted served as the Director of R&D for the Accredited Gemological Association in the USA. He has collaborated with various organizations in the gem industry, such as CIBJO, AGS, NAJA, GAAB, and TGJTA. He has conducted 50+ seminars for gemological associations worldwide; he published over 110 articles on gem treatments, identification, detection, instrumentation, and other gemstone-related issues. Since 2003, he has taught his highly acclaimed hands-on training course in heating ruby and sapphire, training over 250 gem traders, gem treaters, and gemologists worldwide. Over the years, Ted has developed technology and engineered equipment projects for many international clients involving heating ruby-sapphire with over 120 gem treatment installations globally. His gem-treating laboratory in Thailand produces and sells gem-treatment equipment and specialized instruments and provides consultation to the gemstone industry.