关键词: 尖晶石, 合成尖晶石, 焰熔法, 提拉法, 宝石学性质, 光谱特征

Abstract:  As spinels have gained increasing popularity in international colored gemstone trading, a largenumber of "high-quality" synthetic spinels have become available. Inspectionshave revealed that, besidesthe common blue varieties synthesizedby the flame fusion method, these synthetic spinels also include newred-pink varieties synthesized by the Czochralski method, which are indistinguishable from natural spinels.Conventional gemological identification instruments, including Fourier transform infrared (FTIR) spectrom-eters and ultraviolet-visible (UV-Vis) spectrophotometers, were employed to analyze the gemological prop-erties and spectral characteristics of both natural and synthetic spinel samples. Research indicates that thegemological properties of synthetic spinels closely resemble those of spinels, and identifying typical internalinclusions is the key to identification. Infrared (IR) spectroscopy revealed that spinels exhibit three ab-sorption peaks at 543, 590, and 732 cm "1, whereas flame fusion-synthesized spinels exhibit three absorp-tion peaks at 547, 725, and 844 cm~1. Testing revealed that Czochralski-synthesized spinels lack the ab-sorption peak at 590 cm-1 found in spinels, exhibiting only two absorption peaks at 547 and 748 cm~1This evidence serves as a significant identification characteristic for Czochralski-synthesized spinels. UV-Vis spectroscopy indicated that red spinels and Czochralski-synthesized spinels are colored by chromium,blue spinels by iron, and blue flame fusion-synthesized spinels by cobalt. Hence, to effectively differentiate spinels from synthetic spinels in practical testing, it is necessary to combine spectral characteristics.

Key words: spinel, synthetic spinel, Flame Fusion method, Czochralski Method, gemological properties;spectral characteristics