Furnaces

GEMLAB FURNACES FOR HEATING RUBIES-SAPPHIRES, OTHER GEMSTONES

Based on 40 years of experience in gemstone treatments, we have determined that a vertical muffle configuration is the optimal design for heating up to 3,200 carats of rubies, sapphires, and other colored gemstones to 1700°C. Our furnaces, meticulously designed and fabricated in our Bangkok workshop-laboratory, are built around essential heating parameters: temperature profiles, atmospheric conditions, and chemical additives. Please note, we do not provide the “know-how” for gemstone heating; we sell equipment according to its specifications, capabilities, and limitations. Novices are encouraged to study Ted Themelis’ monographs No.1-7 for detailed guidance on ruby-sapphire heat treatment, which will help users achieve accurate heating parameters within the gem material’s tolerances.

Model M80P-1700 Bottom-loading vertical alumina tube muffle furnace to 1720°C

The Gemlab Model M80P-1700 (“MAXXI MUFFLE”) is a state-of-the-art, all-in-one vertical muffle furnace, designed by Ted Themelis for superior performance and longevity. This bottom-loaded furnace features four integrated modules: Power Module, Furnace Module, Temperature Control Module, and Atmosphere Control Module. It can heat-treat up to 3,380 carats of rubies and sapphires at temperatures reaching 1700°C in various conditions, including air, reducing or oxidizing atmospheres, and vacuum up to 1500°C. For specific processes, it can also operate without the muffle to increase capacity.

Model M50P-1700 Bottom-loading vertical alumina tube muffle furnace to 1720°C

The Gemlab Model M50P-1700 (“MINI MUFFLE”) is a compact, bottom-loaded vertical muffle furnace designed by Ted Themelis to meet the demand for a reliable, mini-sized, desktop furnace. It features a manually operated mechanical elevator for easy loading and unloading of rubies and sapphires into the heating chamber. The furnace can heat-treat up to 1,140 carats of rubies-sapphires at temperatures up to 1700°C in air, reducing or oxidizing atmospheres, or vacuum, with or without additives. It can also operate without the muffle to increase capacity for certain heating processes.

Model V50-1300 Top-loading vertical alumina tube muffle furnace to 1300°C

The Gemlab Model BV50-1300 is a feather-weight, desktop furnace designed by Ted Themelis, offering exceptional economy and minimal workspace footprint. As a top-loading vertical muffle furnace, it features unparalleled versatility and superior design, unmatched in the industry. This furnace can heat-treat gemstones for extended periods—days, weeks, or months—under various conditions, including air, oxidizing atmospheres, nitrogen-controlled atmospheres, or vacuum, with or without chemical additives.