Not all instruments used to solve gemological problems can be used in gemological laboratories. Many advanced technologies, such as electron paramagnetic resonance (EPR/ESR), laser scattering chromatography (LST), nuclear magnetic resonance (NMR), X-ray diffraction analysis (XRD), particle-induced X-ray fluorescence analysis (PIXE), X-ray photoelectron spectroscopy (XPS), X-ray morphology, transmission electron microscope (TEM) and so on. From the perspective of development and scientific progress, these instruments will play an active role in identifying the origin of colored gems. The following briefly introduces several methods and their applications.

(1) Electron Paramagnetic Vibration

EPR, also known as electron spin * * * vibration (ESR), has been used to study valence states and chemical bonds of some transition metal elements in gemstones. This is a magnetic * * vibration technology derived from the magnetic moment of unpaired electrons. It can be used to qualitatively or quantitatively detect unpaired electrons contained in atoms or molecules of matter and explore the structural characteristics of its surrounding environment. For free radicals, the orbital magnetic moment has little influence, and most of the total magnetic moment (more than 99%) is contributed by electron spin, so the electron paramagnetic vibration is also called "electron spin * * * vibration (ESR)". Electron paramagnetic resonance spectroscopy has existed for more than 50 years, but it has not been widely used in gemology. The test sample is placed in a high-frequency microwave field and in a strong and variable magnetic field. Ions containing unpaired electrons will strongly absorb microwaves in a specific magnetic field. EPR is very sensitive to the detection of specific components, and can be used to detect oxygen ions formed in ultra-high temperature treated gem materials, such as beryllium diffused corundum.

(2) Laser Scattering Tomography (LST)

This is a nondestructive microscope detection technology that obtains 90 scattering tomography by laser scattering. Using this technology, the micro-defects in heat-treated sapphire and synthetic ruby were imaged, analyzed and compared in the former Japan Baoxie Laboratory.

(3) nuclear magnetic resonance

This is a nondestructive testing technology based on the interaction between nucleus and magnetic field, which has been widely used in life science, medicine, material science and other disciplines. This technology can be used to determine the structure of many objects, such as the crystallinity of polymer compounds, the three-dimensional configuration composition of polymer chains, the composition of drugs, the structure of biomacromolecules, drugs, the interaction between biomacromolecules and cell receptors, the water content of living tissues, cancer diagnosis, NMR-CT scanning of human bodies and so on. At present, it is mainly used for the research of jewelry and jade materials, and for the age research and optimization identification of amber. In addition, through the study of specific elements such as hydrogen and fluorine, some natural and synthetic emeralds and heat-treated aquamarine can be distinguished. In the future, this method will play a greater role in the research and identification of jewelry and jade.

(4) X-ray diffraction analysis (XRD)

The instrument is a method for structural analysis of the spatial distribution of atoms in matter by using X-ray diffraction formed by crystals. When X-rays with a certain wavelength are irradiated on a crystal substance, the X-rays are scattered because they meet atoms or ions arranged regularly in the crystal, and the phase of the scattered X-rays is strengthened in some directions, thus showing a unique diffraction phenomenon corresponding to the crystal structure. X-ray diffraction method has the advantages of no damage to the sample, no pollution, high speed, high measurement accuracy and can provide a lot of crystal integrity information. This method is widely used in gemology to identify the varieties and inclusions of jewelry and jade. In the collection of origin information, the mineral composition and structure of inclusions in gemstones are mainly studied by X-ray diffraction microanalysis technology.

(5) Particle-induced X-ray fluorescence analysis (PIXE)

It is an important technology of high energy particle beam analysis. PIXE analysis has the characteristics of sensitivity, rapidity, less sampling and nondestructive analysis. This method is very sensitive to most elements (Z≥ 12), and the relative sensitivity is 10-6. Multiple elements can be detected in one measurement, and microbeam can also be used. At present, due to the high cost of equipment, the use of this instrument has only been reported in articles such as physical research and archaeology of loose jewelry materials.

(6) X-ray photoelectron spectroscopy (XPS)

Irradiate the sample with X-rays, so that the inner electrons or valence electrons of atoms or molecules are excited and emitted. The detector can measure the energy of excited photoelectrons, and make the photoelectron spectrum with the kinetic energy of photoelectrons as the abscissa and the relative intensity (pulse/second) as the ordinate, thus obtaining the chemical element composition of the measured object. XPS mainly measures the binding energy of electrons to realize the qualitative analysis of surface elements, including valence state analysis. X-ray photoelectron spectroscopy is the most effective chemical analysis method. This technology is mainly used to detect the elemental composition and oxidation state of samples in gemmological research and identification, and to identify the surface coating materials of jewelry and jade. It is similar to infrared spectroscopy to detect the surface of jadeite by injecting wax or polymer.

(7) X-ray morphological method (XT)

X-ray geomorphology, also known as X-ray geomorphology, is a method to inspect the surface and internal microstructure defects of crystal materials and devices according to the change of diffraction contrast and the law of astigmatism in crystals. It has the advantages of nondestructive testing, convenient sample preparation, good experimental repeatability, and can determine the nature of defects, and is widely used in the study of crystal material integrity. With the development of science and technology and the wide use of near-complete crystal materials, the research on X-ray morphology technology and X-ray diffraction dynamics theory has made great progress since the late 1950s, and has gradually become an important means of inspection and a branch of material science. In the research of jewelry materials, this method is mainly used to study some industrial varieties such as diamonds, crystals and sapphires. In the future, this technology is expected to be used to identify the origin of colored gems.