Number. It is non-repeatable, and testing units can use it to find the bottom. (2) Photograph, shape, color, transparency, weight and size, etc. They not only explain the basic situation of the tested sample, but also have the significance of calibrating the sample to prevent the certificate from being crowned. If someone is an impostor, they can be identified by these data. ③ Refractive index, glossiness, relative density, fluorescence characteristics and microscopic observation results. This is the main basis for confirming what the tested sample is. Without these data, or only one or two projects, the reliability of the conclusion is doubtful. In addition, they should be measured results, not theoretical values or speculative results. ④ Identification results.