【正文】 en the case with successful jewelry lines, less expensive approaches soon followed. ? Harris and Vance (1972) had experimented with the production of artificial graphitization in diamond, which Hall and Moses (2023 a) confirmed by heating a sample under vacuum for a few minutes to several hours and turning it black。 Smith et al., 2023). All had one consistent characteristic: a colorless or nearcolorless outer rim and a deep blue (or, if color change, purple) interior (figure 6). ? Figure 5. This matched pair of blue sapphires ( and ct) were heat treated by the Punsiri method. Photo by Maha Taanous. ? Figure 6. The unusual color zoning in this colorchange sapphire is typical of stones treated by the Punsiri method. Photomicrograph by S. F. McClure。 McClure and Smith, 2023), heattreatment technology— in the form of electric furnaces with precise temperature and atmospheric controls—has bee more sophisticated and accessible. During the 1980s and 1990s, nearly all mercial corundum heat treatment was being conducted in Thailand. ? While Thailand remains important, Sri Lanka is now a major force, and smaller yet very effective corundumheating capabilities exist in other producing regions such as Africa, Myanmar, China, and the . (Montana). Nevertheless, some pink sapphires and rubies continue to be heated using simple blowpipe methods at mine sites and trading centers in Vietnam, Sri Lanka, and elsewhere (R. Hughes, pers. m., 2023). ? Heat treatment, particularly at high temperatures, can dramatically alter the internal characteristics and properties of sapphires and rubies. During the past decade, a number of articles addressed heattreatment techniques and their effects on gem corundum from localities such as Madagascar (Wang et al., 2023a), Montana (Schmetzer and Schwarz, 2023。 colored halos surrounding altered solid mineral inclusions。 see Shor and Weldon (2023) and Shigley et al. (2023) for important literature references. Smith et al. (2023d) and Smith (2023) provided useful charts for identifying the natural or treated state in rubies and sapphires from around the world. 謝謝觀看 /歡迎下載 BY FAITH I MEAN A VISION OF GOOD ONE CHERISHES AND THE ENTHUSIASM THAT PUSHES ONE TO SEEK ITS FULFILLMENT REGARDLESS OF OBSTACLES. BY FAITH I BY FAITH 。 and pockmarked, resorbed facets. ? Relatively lowtemperature heating (1200176。 Rankin and Edwards, 2023). ? Schmetzer and Schwarz (2023) discussed the identification of natural, heated, and Bediffused yellow to reddish orange sapphires from Sri Lanka, Montana, Madagascar, and Tanzania. David and Fritsch (2023) contributed a valuable study on the use of infrared spectra to distinguish heated rubies and sapphires from 20 different geographic origins. ? Proof that a ruby or sapphire has been heat treated is sometimes readily apparent, but in many cases it requires considerable knowledge and observational skills. The criteria for identifying heat treatment in rubies and sapphires using a microscope were set forth during the 1980s and 90s (for a summary, see Kammerling et al., 1990a). ? Most still apply. They include stress fractures surrounding melted or heataltered inclusions。 Hanni et al., 2023。 figure 4). ? Figure 4. Heat treatment with the stone placed in a flux has largely healed this fracture in a Mong Hsu ruby. However, it has left behind a fingerprint that looks similar to those found in synthetic rubies, another challenge for the gemologist. Photomicrograph by S. F. McClure。 see, ., figure 3). ? Figure 3. This ct Fancy Light grayblue diamond was successfully turned Fancy blue by HPHT treatment. Ph