GRS Gemresearch: Unusual Phosphorescent Pebbles Identified as Synthetic Aggregates
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8 سال پیش
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Phosphorescent pebbles are presented in the market as natural rounded pebbles (3.53 density) possessing extraordinary properties such as green phosphorescence when exposed to a strong light source and patchy blue to green fluorescence in short- and long wave UV-light, again with green phosphorescence (no blue).
Such items appeared multiple times in the last two years at our laboratories. They are sold at very high prices of thousands of US dollars per piece or sometimes even per carat. The first specimen we have tested, initially appeared in Burma (Myanmar) in 2014. Similar material appeared as carvings on the Chinese market according to an article published on the website of the Gems & Jewelry Trade Association of China.
The analyses showed that this material is a synthesized aggregate material (Figure 4). The material was first synthetized in Russia in 1976 as Sr4Al14O25 and published by Nadezzhina (1976), Kristallografiya, 21, 826. The literature from Chinese researchers (Chengkang et al. 2006) confirmed that this type of material was later doped with Europium (Eu) on Strontium (Sr) position, which creates phosphorescence.
Detailed XRD analyses revealed that the material we had tested also contained a minor secondary synthetic phase of SrAl2O4 in addition to the material mentioned above, actually identifying the pebbles as an aggregate of two structurally different synthetic substances. Additional ED-XRF analyses confirmed the elements Strontium (Sr) and Aluminum (Al) but showed that instead of Europium (Eu), the major REE element was Dysprosium (Dy).
Phosphorescent pebbles are presented in the market as natural rounded pebbles (3.53 density) possessing extraordinary properties such as green phosphorescence when exposed to a strong light source and patchy blue to green fluorescence in short- and long wave UV-light, again with green phosphorescence (no blue).
Such items appeared multiple times in the last two years at our laboratories. They are sold at very high prices of thousands of US dollars per piece or sometimes even per carat. The first specimen we have tested, initially appeared in Burma (Myanmar) in 2014. Similar material appeared as carvings on the Chinese market according to an article published on the website of the Gems & Jewelry Trade Association of China.
The analyses showed that this material is a synthesized aggregate material (Figure 4). The material was first synthetized in Russia in 1976 as Sr4Al14O25 and published by Nadezzhina (1976), Kristallografiya, 21, 826. The literature from Chinese researchers (Chengkang et al. 2006) confirmed that this type of material was later doped with Europium (Eu) on Strontium (Sr) position, which creates phosphorescence.
Detailed XRD analyses revealed that the material we had tested also contained a minor secondary synthetic phase of SrAl2O4 in addition to the material mentioned above, actually identifying the pebbles as an aggregate of two structurally different synthetic substances. Additional ED-XRF analyses confirmed the elements Strontium (Sr) and Aluminum (Al) but showed that instead of Europium (Eu), the major REE element was Dysprosium (Dy).
8 سال پیش
در تاریخ 1395/02/06 منتشر شده
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