Abstract: The cenozoic magmatic activity in the eastern coastal areas of China is intense, and the Wenchang area of Hainan Province is an important represent where gem-quality zircon crystals are produced in the sedentary products of alkaline basalt. In this study, the gemmological and mineralogical characteristics of zircon samples from the secondary deposit in Wenchang were studied in order to obtain the spectral characteristics, and to explore the correlation between the degree of decrystallization and spectral characteristics of zircon samples. The trace element test results show that the content of Ti is generally low and the Th/U ratio is relatively high, indicating that its formation is closely related to the magmatic environment. The average age is 3.78±0.10 Ma by the U-Pb age method. The Raman spectrum results show that the zircon samples from Wenchang generally have a low metamorphic degree.The zircon radioactive flux Dα shows a negative correlation with the Raman shift peak caused by the ν₃(SiO₄) vibration and a positively correlated with its full width at half maximum. The crystallinity and colour of zircon could be improved by heated treatment.The obvious colour changes from dark brown to reddish brown or colourless of the zircon samples could be observed, when heated to 600 ℃ in air and nitrogen surroundings, respectively. The colour changes are mainly related to the absorption in the range of 440-550 nm which is related to the formation and elimination of colour center, the repair of lattice damage, and the concentration of rare earth and radioactive elements in zircon. When heated to 1 100 ℃ in nitrogen atmosphere, the colour change from dark brown to blue-gray of zircon samples may be related to the transformation of U⁵⁺+e^-→U⁴⁺.