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In this course edition the course #510 is updated and the practical sessions are expanded to include 4 heating processes performed by the students. The newest Pb+Co process for blue sapphire will be discussed in detail; new information on ruby-sapphire treatments are constantly added... |
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| Sept. 3-7, 2013 |
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In May 2013, our company has opened a service center in SRI LANKA to provide technical support to our Sri Lankan customers who bought our furnaces. This new Sri Lankan company THEMELIS COMPANY (PVT) LTD is entirely owned by Ted and Angelo Themelis and it is subsidiary of our 37 year company GEMLAB which is based in Thailand and USA. Angelo Themelis, the Managing Director of the new company, is now residing in Sri Lanka providing support, installation, repair service and training for all the products we fabricate and sell.
The company supplies high quality alumina crucibles, alumina muffle tubes, thermocouples, heating elements and other spare parts for all our products.
In June 2013, prospective customers will have the opportunity to view and experience personally our new furnace demonstration models M50-N-1700 and M76-N-1700.
Contact address: THEMELIS COMPANY (PVT) LTD, Sri Lanka - Angelo Themelis Mobile: (94) 071-992-3131 |
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The most authoritative book on the subject is now OUT OF PRINT. New edition is expected to be ready withing 2013. Contact us. |
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The word "gem" should be redefined. Heavily treated gems are actually semi-synthetic, hybrid, or composite products and do not qualify to be called “GEMS”. Only untreated gems should be called “GEMS”. –Dr. FrankenStone, Grandmaster of Gem Treatments |
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“Cobalt-lead-glass filled blue sapphires” are now available for sale by Ted Themelis directly from his Gemlab Kitchen in Bangkok. These blue sapphires have been heat-treated with lead, silica, sodium, potassium and other additives with cobalt added for color, using “FRIT” technology. The sapphires are transparent to semi-transparent with good blue color throughout the substance where their surface-reaching cracks are filled. The color is not confined at the surface of the stone, like the similarly appearing Cobalt treated "Tanyrson" blue sapphires; the treatment is easily detectable; these stones are not stable and require special care as they may be damaged when soaked in acids or during jewelry repairs.
Gemlab offers these blue “fritted” sapphires weighing about 1 to 3 carats each for $20/carat with minimum order of $60, including postage worldwide. All stones have interesting inclusion features, great for study and reference specimens for gemologists, gemological laboratories, jewelers and just about everyone involved in the gemstone industry. Contact us now for immediate delivery. |
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Pb+Co blue sapphires, the newest addition of the heated stones from the Bangkok Gem Kitchens. Variations of the Pb+Co blue sapphires is underway and soon they will hit the market. |
Pb+Co blue sapphire sliced to show that the color is throughout the substance, not confined at its surface, or sub-surface. |
Pb+Co blue sapphires cut in halve; one halve was immersed overnight in a bitter Thai lemon juice (right); the other half (left) was untested serving as a control sample. |
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As promised the new generation of heat-treated gems arrived. Ted is now treating with new innovative methodology untreated (or previously treated) rubies, sapphires, spinels, grossulars and other gems utilizing flux-aided addives including lithium, boron, sodium, aluminum and silicon at temperatures 650oC to 1350oC for soaking periods ranging from few minutes to several days. On certain type of stones, this treatment is based on Lithium additives and removes the purple tinge from rubies; brown tinge from red-brown spinels; brown tinge from spessartites-hessonites. The new treatment also enhances the clarity, transparency, luster and brilliance on selected types of gems. Lithium-treated rubies show rutile needles and particles; rarely show growth pattern; commonly show twin lammellae; distorted zircon and other guest mineral inclusions. Detection of the treatment range from easy to very difficult; a lab issued a Gemstone Report declaring the stone "untreated"; another lab couldn't detect lithium -the key ingredient of the flux- using LAICPMS. The decolorization mechanism (removing the brownish tinge) and color alteration of the lithium-treated stones is unknown. But the fact is that the color of these Lithium-treated stones is distributed throughout the lattice of the crystal, not confined at/below their surface and have nothing to do with the surface-subsurface treated gems. All gems treated by Ted are stable and durable to light and normal wear (as their untreated counterparts); the treatment does not create special care under normal “wear-and-tear” and the process is permanent, repeatable and irreversible. All these Lithium-treated gems are sold with full disclosure (see Gemstone ID-card). Stay tune as the new gemologist's nightmare is around the corner from Dr. Franken-STONE. |
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Grossular |
Ruby |
Sapphire |
Spinel |
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