Method for identifying pink sapphire synthesized by heat exchange method and natural pink sapphire

Abstract

The invention discloses a method for identifying a pink sapphire synthesized by a heat exchange method and a natural pink sapphire, which comprises the following five steps: S1, carrying out ultraviolet-visible spectrum detection on a sample to be detected to obtain a corresponding ultraviolet-visible spectrogram; s2, taking an ultraviolet-visible spectrogram of the sample obtained in the step S1, and judging that the pink sapphire and the natural pink sapphire are synthesized by a heat exchange method according to reflection spectrum characteristics in a 200-700nm interval in the spectrogram; s3, performing photoluminescence detection on the sample to obtain a corresponding photoluminescence spectrogram; s4, taking the photoluminescence spectrogram of the sample obtained in the step S3, and judging the pink sapphire synthesized by the heat exchange method and the natural pink sapphire according to the intensity characteristics at the interval of 650-800nm in the spectrogram; and S5, sample identification. By adopting ultraviolet visible spectrum detection and photoluminescence spectrum detection, natural pink sapphire and pink sapphire synthesized by a heat exchange method can be quickly, accurately and nondestructively identified.

Description

Technical Field

[0001] This invention belongs to the field of gem identification technology, and in particular relates to a method for distinguishing between synthetic pink sapphire obtained by heat exchange method and natural pink sapphire. Background Technology

[0002] Sapphire is one of the world's most recognized precious colored gemstones. Like ruby, it belongs to the corundum mineral family, with Al₂O₃ as its main component, except for the presence of Cr. 3+ Replace Al 3+ Aside from rubies, which exhibit a reddish hue due to their position in the crystal lattice, all other colored corundum is called sapphire. Therefore, sapphires come in colors such as pink, yellow, green, and colorless. Natural sapphires, as beautiful and valuable mid-to-high-end colored gemstones, occupy an important position in the jewelry market.

[0003] Expensive natural sapphires have many similar and synthetic products on the market. Synthetic sapphires available include those synthesized using the Czochralski method, flame fusion method, flux method, and Czochralski method. Currently, the gemological and spectroscopic characteristics of synthetic sapphires synthesized using these methods are primarily being studied. Recently, a heat exchange method for synthesizing sapphires has emerged on the market, exhibiting exceptional internal cleanliness. The basic principle of the heat exchange method is to use a heat exchanger to remove heat, creating a vertical temperature gradient within the growth furnace, with the bottom cooled and the top heated. The temperature field is controlled by adjusting the gas flow rate and heating power within the heat exchanger, thereby achieving crystal growth. Essentially, it is a controlled directional solidification crystallization method, primarily used for growing high-quality, large-size sapphire crystals.

[0004] Currently, research on the gemological and typical spectroscopic characteristics of heat-exchange synthetic sapphires is insufficient, and there are no clear identification indicators for accurate judgment. It is difficult to quickly and accurately distinguish between heat-exchange synthetic sapphires and natural sapphires. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned technical problems existing in the prior art and to provide a method for distinguishing between synthetic pink sapphire and natural pink sapphire by heat exchange method. This method can quickly, accurately and non-destructively distinguish between natural pink sapphire and synthetic pink sapphire by heat exchange method.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A method for distinguishing between synthetic pink sapphire obtained by heat exchange and natural pink sapphire, characterized by comprising the following steps: S1. Perform ultraviolet-visible spectral detection on the sample to be tested to obtain the corresponding ultraviolet-visible spectrum. The horizontal axis of the ultraviolet-visible spectrum is wavelength, with a wavelength range of 200-900nm; the vertical axis is reflectance, with a reflectance range of 0-100%, and the integration time is 60-120s. S2. Take the UV-Vis spectrum of the sample obtained in step S1, and determine whether the pink sapphire synthesized by heat exchange method or the natural pink sapphire is based on the reflectance spectral characteristics in the 200-700nm range of the spectrum. S3. Perform photoluminescence detection on the sample to obtain the corresponding photoluminescence spectrum. The horizontal axis of the photoluminescence spectrum is wavelength, with a wavelength range of 200-1000nm, and the vertical axis is intensity. The integration time is 60-120s. S4. Take the photoluminescence spectrum of the sample obtained in step S3, and judge the difference between the heat exchange method synthesized pink sapphire and natural pink sapphire based on the intensity characteristics in the 650-800nm ​​range of the spectrum. S5. If a sample meets both the criteria for UV-Vis spectroscopy and photoluminescence detection, then the sapphire is a synthetic pink sapphire obtained by heat exchange method. If a sample meets both the criteria for UV-Vis spectroscopy and photoluminescence detection, then the sapphire is a natural pink sapphire.

[0007] Furthermore, in step S1, the integration time is 90s, the average number of iterations is 20, and the smoothing width is 1cm.

[0008] Furthermore, in step S2, if the sample has absorption bands in the ranges of 330-340nm, 400-410nm, and 550-560nm, then the sample is a natural pink sapphire; if the mesa has absorption bands in the ranges of 360-370nm, 420-430nm, 485-495nm, and 560-570nm, and the pavilion has a broad absorption band in the ranges of 340-350nm and 500-560nm, then the sample is a pink sapphire synthesized by the heat exchange method.

[0009] Furthermore, in step S2, the 690-700nm range contains Cr 3+ The fluorescence emission peak indicates that the sample is a natural pink sapphire.

[0010] Furthermore, in step S2, the sample with an absorption cutoff edge in the 295-305nm range is natural pink sapphire.

[0011] Furthermore, in step S2, the samples with absorption peaks in the 485-495nm and 560-570nm ranges are pink sapphires synthesized by the heat exchange method.

[0012] Furthermore, in step S2, the sample with an absorption cutoff edge in the 250-260nm range is a pink sapphire synthesized by the heat exchange method.

[0013] Furthermore, in step S3, the integration time is 90s, the average number of times is 20, the smoothing width is 1cm, the excitation light source is 405nm, and the sample is detected under liquid nitrogen conditions and room temperature conditions respectively.

[0014] Furthermore, in step S4, 690-700cm -1 Samples with sharp peaks in the 745-755nm range are natural pink sapphires; samples with broad peaks in the 745-755nm range are synthetic pink sapphires obtained through heat exchange.

[0015] Furthermore, during the sample testing process, both the platform and the pavilion of the sample were tested.

[0016] The present invention, by adopting the above-described technical solution, has the following beneficial effects: This invention, by employing ultraviolet-visible spectroscopy and photoluminescence spectroscopy, can quickly, accurately, and non-destructively identify natural pink sapphire and synthetic pink sapphire obtained through heat exchange. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings: Figure 1 This is the ultraviolet-visible spectrum of the pavilion section of the natural pink sapphire in this invention; Figure 2 This is the ultraviolet-visible spectrum of the natural pink sapphire table in this invention; Figure 3 This is the ultraviolet-visible spectrum of the pavilion of pink sapphire synthesized by the heat exchange method in this invention; Figure 4 This is the ultraviolet-visible spectrum of the pink sapphire mesa synthesized by the heat exchange method in this invention; Figure 5 This is the photoluminescence spectrum of natural pink sapphire under liquid nitrogen conditions in this invention; Figure 6 This is the photoluminescence spectrum of the natural pink sapphire in this invention under room temperature conditions; Figure 7 This is the photoluminescence spectrum of pink sapphire synthesized by the heat exchange method in this invention under liquid nitrogen conditions; Figure 8 This is the photoluminescence spectrum of pink sapphire synthesized by the heat exchange method in this invention at room temperature. Detailed Implementation

[0018] The present invention provides a method for distinguishing between synthetic pink sapphire obtained by heat exchange method and natural pink sapphire, comprising the following steps: S1. Perform ultraviolet-visible spectral detection on the sample to be tested to obtain the corresponding ultraviolet-visible spectrum. The horizontal axis of the ultraviolet-visible spectrum is wavelength, with a wavelength range of 200-900nm; the vertical axis is reflectance, with a reflectance range of 0-100%, and the integration time is 60-120s. S2. Take the UV-Vis spectrum of the sample obtained in step S1, and determine whether the pink sapphire synthesized by heat exchange method or the natural pink sapphire is based on the reflectance spectral characteristics in the 200-700nm range of the spectrum. S3. Perform photoluminescence detection on the sample to obtain the corresponding photoluminescence spectrum. The horizontal axis of the photoluminescence spectrum is wavelength, with a wavelength range of 200-1000nm, and the vertical axis is intensity. The integration time is 60-120s. S4. Take the photoluminescence spectrum of the sample obtained in step S3, and judge the difference between the heat exchange method synthesized pink sapphire and natural pink sapphire based on the intensity characteristics in the 650-800nm ​​range of the spectrum. S5. If a sample meets both the criteria for UV-Vis spectroscopy and photoluminescence detection, then the sapphire is a synthetic pink sapphire obtained by heat exchange method. If a sample meets both the criteria for UV-Vis spectroscopy and photoluminescence detection, then the sapphire is a natural pink sapphire.

[0019] In step S1, the integration time is 90s, the average number of iterations is 20, and the smoothing width is 1cm.

[0020] In step S2, if the sample has absorption bands in the ranges of 330-340nm, 400-410nm, and 550-560nm, then the sample is a natural pink sapphire; if the mesa has absorption bands in the ranges of 360-370nm, 420-430nm, 485-495nm, and 560-570nm, and the pavilion has a broad absorption band in the ranges of 340-350nm and 500-560nm, then the sample is a pink sapphire synthesized by the heat exchange method.

[0021] In step S2, the 690-700nm range contains Cr 3+ The fluorescence emission peak indicates that the sample is a natural pink sapphire.

[0022] In step S2, the sample with an absorption cutoff edge at 295-305nm is natural pink sapphire.

[0023] In step S2, the sample with absorption peaks at 485-495nm and 560-570nm is a pink sapphire synthesized by the heat exchange method.

[0024] In step S2, the sample with an absorption cutoff edge at 250-260 nm is a pink sapphire synthesized by the heat exchange method.

[0025] In step S3, the integration time is 90s, the average number of iterations is 20, the smoothing width is 1cm, the excitation light source is 405nm, and the sample is detected under liquid nitrogen conditions and room temperature conditions respectively.

[0026] In step S4, 690-700 cm -1 Samples with sharp peaks on the left and right are natural pink sapphires; samples with broad peaks at 745-755nm are synthetic pink sapphires obtained through heat exchange.

[0027] During the sample testing process, both the platform and the pavilion of the sample are tested.

[0028] Example: Eleven experimental samples were prepared and numbered sequentially as follows: hc-1, hc-2, hc-3, hc-4, hc-5, wf-1, wf-2, wf-3, wf-4, yf-1, yf-2. The samples were then tested sequentially according to the identification method.

[0029] The instrument used for ultraviolet-visible spectroscopy was a GEM UV-100 with an integration time of 90 s, an average number of 20 times, a smoothing width of 1 cm, and a wavelength range of 200-900 nm. The reflectance method was employed.

[0030] The photoluminescence detection instrument was a Biaoqi Optoelectronics GEM-3000, with an integration time of 90 s, an average number of iterations of 20, a smoothing width of 1 cm, a wavelength range of 200-1000 nm, and an excitation source of 405 nm. Samples were detected under liquid nitrogen conditions (approximately 77 K) and room temperature conditions (approximately 293 K).

[0031] During the testing of samples wf-1, wf-2, wf-3, wf-4, yf-1, and yf-2, the test results for the platform and the pavilion were consistent. For example... Figure 1 and Figure 2 As shown, samples wf-1, wf-2, wf-3, wf-4, yf-1, and yf-2 exhibit broad absorption bands near 336 nm, 407 nm, and 558 nm in their UV-Vis spectra, with strong Cr absorption visible at 694 nm. 3+ The fluorescence emission peak has an absorption cutoff edge around 300 nm, and the absorption band near 302 nm is due to Fe. 3+ The dd transition leads to Cr 3+ d-electron transition 4 A2→ 4 T1, 4 A2→ 4T2 resulted in absorption bands at 407 nm and 558 nm, which also correspond to blue-violet and yellow-green absorption, thus giving the samples varying degrees of red hues. It can be determined that wf-1, wf-2, wf-3, wf-4, yf-1, and yf-2 meet the characteristics of natural pink sapphire in UV-Vis spectroscopy.

[0032] like Figure 5 and Figure 6 As shown, in the photoluminescence spectra of samples wf-1, wf-2, wf-3, wf-4, yf-1, and yf-2, at 693 cm⁻¹... -1 The presence of sharp peaks on both sides indicates that wf-1, wf-2, wf-3, wf-4, yf-1, and yf-2 meet the characteristics of natural pink sapphire in photoluminescence spectroscopy.

[0033] Therefore, samples wf-1, wf-2, wf-3, wf-4, yf-1, and yf-2 were identified as natural pink sapphires.

[0034] During the detection process, the UV-Vis spectra of samples hc-1, hc-2, hc-3, hc-4, and hc-5 differed in different directions. For example... Figure 3 and Figure 4 As shown, the mesa of the sample exhibits absorption bands near 365 nm, 422 nm, 490 nm, and 565 nm. The pavilion of the sample shows broad absorption bands at 344 nm and 500-560 nm, with an absorption peak at 422 nm. The absorption peaks near 490 nm and 565 nm are due to Ti. 3+ The coloration exhibits typical UV-Vis absorption spectral characteristics. Additionally, an absorption peak at 422 nm appears in both UV-Vis directions, which may be due to Ti. 4+ The fluorescence peak of charge transfer has an absorption cutoff edge of around 256 nm. This indicates that samples hc-1, hc-2, hc-3, hc-4, and hc-5 meet the characteristics of pink sapphire synthesized via heat exchange in UV-Vis spectroscopy.

[0035] like Figure 7 and Figure 8 As shown, samples hc-1, hc-2, hc-3, hc-4, and hc-5 exhibit a broad peak around 750 nm in their photoluminescence spectra, indicating that samples hc-1, hc-2, hc-3, hc-4, and hc-5 meet the characteristics of pink sapphire synthesized by the heat exchange method in UV-Vis spectroscopy.

[0036] Therefore, samples hc-1, hc-2, hc-3, hc-4, and hc-5 were identified as characteristic of pink sapphires synthesized by the heat exchange method.

[0037] This invention, by employing ultraviolet-visible spectroscopy and photoluminescence spectroscopy, can quickly, accurately, and non-destructively identify natural pink sapphire and synthetic pink sapphire obtained through heat exchange.

[0038] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.

Claims

1. A method for distinguishing between synthetic pink sapphire obtained by heat exchange method and natural pink sapphire, characterized in that... Includes the following steps: S1. Perform ultraviolet-visible spectral detection on the sample to be tested to obtain the corresponding ultraviolet-visible spectrum. The horizontal axis of the ultraviolet-visible spectrum is wavelength, with a wavelength range of 200-900nm; the vertical axis is reflectance, with a reflectance range of 0-100%, and the integration time is 60-120s. S2. Take the UV-Vis spectrum of the sample obtained in step S1, and determine whether the pink sapphire synthesized by heat exchange method or the natural pink sapphire is based on the reflectance spectral characteristics in the 200-700nm range of the spectrum. S3. Perform photoluminescence detection on the sample to obtain the corresponding photoluminescence spectrum. The horizontal axis of the photoluminescence spectrum is wavelength, with a wavelength range of 200-1000nm, and the vertical axis is intensity. The integration time is 60-120s. S4. Take the photoluminescence spectrum of the sample obtained in step S3, and judge the difference between the heat exchange method synthesized pink sapphire and natural pink sapphire based on the intensity characteristics in the 650-800nm ​​range of the spectrum. S5. If a sample meets both the criteria for UV-Vis spectroscopy and photoluminescence detection, then the sapphire is a synthetic pink sapphire obtained by heat exchange method. If a sample meets both the criteria for UV-Vis spectroscopy and photoluminescence detection, then the sapphire is a natural pink sapphire.

2. The method for distinguishing between synthetic pink sapphire and natural pink sapphire according to claim 1, characterized in that: In step S1, the integration time is 90s, the average number of iterations is 20, and the smoothing width is 1cm.

3. The method for distinguishing between synthetic pink sapphire and natural pink sapphire according to claim 1, characterized in that: In step S2, if the sample has absorption bands in the ranges of 330-340nm, 400-410nm, and 550-560nm, then the sample is a natural pink sapphire; if the mesa has absorption bands in the ranges of 360-370nm, 420-430nm, 485-495nm, and 560-570nm, and the pavilion has a broad absorption band in the ranges of 340-350nm and 500-560nm, then the sample is a pink sapphire synthesized by the heat exchange method.

4. The method for distinguishing between synthetic pink sapphire and natural pink sapphire according to claim 3, characterized in that: In step S2, the 690-700nm range contains Cr 3+ The fluorescence emission peak indicates that the sample is a natural pink sapphire.

5. The method for distinguishing between synthetic pink sapphire and natural pink sapphire according to claim 4, characterized in that: In step S2, the sample with an absorption cutoff edge in the 295-305nm range is natural pink sapphire.

6. The method for distinguishing between synthetic pink sapphire and natural pink sapphire according to claim 1, characterized in that: In step S2, the samples with absorption peaks in the 485-495nm and 560-570nm ranges are pink sapphires synthesized by the heat exchange method.

7. The method for distinguishing between synthetic pink sapphire and natural pink sapphire according to claim 6, characterized in that: In step S2, the sample with an absorption cutoff edge in the 250-260nm range is a pink sapphire synthesized by the heat exchange method.

8. The method for distinguishing between synthetic pink sapphire and natural pink sapphire according to claim 1, characterized in that: In step S3, the integration time is 90s, the average number of times is 20, the smoothing width is 1cm, the excitation light source is 405nm, and the sample is detected under liquid nitrogen conditions and room temperature conditions respectively.

9. The method for distinguishing between synthetic pink sapphire and natural pink sapphire according to claim 1, characterized in that: In step S4, 690-700cm -1 Samples with sharp peaks in the 745-755nm range are natural pink sapphires; samples with broad peaks in the 745-755nm range are synthetic pink sapphires obtained through heat exchange.

10. The method for distinguishing between synthetic pink sapphire and natural pink sapphire according to claim 1, characterized in that: During the sample testing process, both the platform and the pavilion of the sample are tested.

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