## 3 Results and Discussion
### DiamondView(tm) and Cathodoluminescence  
The five samples presented different fluorescence images in DiamondView(tm), but none of them had phosphorescence. The specific luminous pattern is shown in Figure 3. Sample R-YG-1 emitted medium green fluorescence, presenting a geometric luminescence pattern of a \"chip\" shape. The growth rings were straight and fine, and some were serrated. The central luminescence was relatively concentrated and uniform, presenting a regular quadrilateral luminescence pattern. Sample R-Y-1 showed weak green and blue fluorescence at the same time, and the whole growth band was fine and straight, with a partial ladder shape. Sample R-Y-2 presented strong yellow-green fluorescence in general, \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sample** & **Color** & **LWWV (Long-Wave Ultraviolet Light:** & **SWUV (Short-Wave Ultraviolet Light:** & **315–400 nm)** & **200–280 nm)** \\ \hline R-YG-1 & Yellow-green & Strong yellow-green & Medium yellow-green \\ R-Y-1 & Yellow & Weak green & Weak orange \\ R-Y-2 & Yellow & Medium yellow-green & Strong yellow-green \\ R-B-1 & Brown & - & - \\ R-P-1 & Purple-red & Medium orange & Medium orange-red \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The ultraviolet fluorescence characteristics of the samples. Figure 2: Black hexagonal sheet inclusions in sample R-P-1 (**a**), colorless crystal inclusions in sample R-YG-1 (**b**), and disc-shaped stress cracks in sample R-Y-1 (**c**). Under orthogonal polarized light, the sample showed more obvious parallel bands (**d**) or corrugated abnormal extinction (**e**), accompanied by strong strain interference color (**f**). and blue fluorescence was seen in local areas. The outer part was a lamellar growth ring, and a structure similar to a \"growth nucleus\" was seen in the center. Sample R-B-1 showed a weak orange fluorescence with blue, straight growth bands. The purple sample R-P-1 showed a strong orange fluorescence, and some showed a yellow and orange fluorescence interphase distribution, which was consistent with the characteristics of the ribbon. In addition, a linear growth pattern was visible, with some of the nearly vertically intersected reticular luminescence patterns. Cathodoluminescence was used to further observe the color patterns of the samples. Under high-energy cathode rays, the luminescence characteristics of the samples were basically the same as those seen in DiamondViewTM, but the luminous intensity under the cathode rays was relatively strong, and the image was sharper, thus providing more detail. Jagged growth textures were seen in the sample R-Y-1. In addition, three groups of fine flat linear textures were visible (Figure 4a). In sample R-Y-2, the edge of the part similar to the \"growth nucleus\" was irregular, and was cut off from the fine, straight, and quadrangular growth ring outside (Figure 4b). In addition to the blue growth ring in the sample R-B-1, a uniform orange luminescence pattern with a regular quadrilateral could be seen (Figure 4c). Sample R-P-1 presented a strip-like luminescence pattern with orange and yellow intersections, and regular laminar growth bands could also be seen inside (Figure 4d). The observation of cathodoluminescence images of diamonds can (1) reveal the internal morphology, growth structure, growth mechanism, growth stage, and process of diamonds; (2) provide the plastic deformation information of diamonds; (3) verify and interpret the results of an infrared spectrum analysis, a stable isotope analysis, and the geological chronology of the diamond microzone; and (4) provide key evidence for distinguishing a natural diamond from a synthetic diamond.