Defining “Low” Temperature While some dealers that we spoke to defined low-temperature treatment as below 1000°C, for research purposes we define it slightly differently. High-temperature treatment involves the dissolution of secondary-phase microcrystals, while low-temperature treatment does not. The most common of these microcrystals in corundum is rutile silk. Rutile dissolution can occur around 1200–1350°C, which we use to define the approximate boundary between low- and high-temperature treatments (Hughes et al., 2017). Because of this, we focused our experiments on four “lower”-temperature rounds of heat ranging from 800 to 1100°C, one “intermediate” round at 1300°C, which we can consider a borderline area, and one “high” round at 1500°C for contrast. 刚玉宝石里最常见的包体是各种形态的金红石包体，金红石包体在1200-1350度开始熔化，所以学术界认为低于1200度的热处理属于“低温”热处理，高于1350度的叫“高温”热处理。（来源于https://lotusgemology.com/index.php/library/articles/456-madagascar-sapphire-low-temperature-heat-treatment-experiments）
