How to identify dyed sapphire
China Jewelry Merchants Network (http://): The Yunnan Lab of the National Jewelry Quality Supervision and Inspection Center recently received three sapphire rings. After laboratory identification, the three sapphires were dyed and filled. sapphire. So, Xiaobian said how to identify the dyed sapphire?
1. The infrared spectroscopy method is used to discriminate the three sapphire species, and the infrared spectrum features are all characteristic absorption peaks of corundum.
2. Refractive index: 1.762-1.769
3. Three sapphire are fluorescently inert under ultraviolet fluorescence.
4. Under the microscope, the cracks on the surface of the three samples developed, the color was enriched along the fissures, and some bubbles were found in the cracks. The gloss of the surface crack pits is significantly different from the surrounding gloss, and is locally accompanied by a flash phenomenon. From this, it can be judged that the three samples were subjected to dyeing and filling treatment.
5. In order to further verify whether the sample has been filled and treated, and the type of filling material used, we have determined the trace elements of the sample. After testing, the sample has the presence of lead (Pb) elements, and the content is relatively high, which is exactly the opposite of the phenomenon that the corundum-type gemstones are Pb-poor. We speculate that the sapphire filling material may be lead glass.
6. The ultraviolet-visible spectrophotometer tests the absorption spectrum of the sample and compares it with the absorption spectrum of natural sapphire. The test sample and the natural sapphire have absorption peaks at 387 nm and 450 nm, but the intensity of the absorption peak at the test sample is stronger than that of the natural sapphire. It is obviously weak; at the same time, an absorption peak appears near 700 nm, and absorption broadband occurs at 580 nm, which is not available in natural sapphire.
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