Natural radiation-induced red fluorescence of fluorite consists of two broad bands at 750 and 635 nm with very short decay times of 20.3 and less than 5 ns, respectively. The first one is connected to an M center compensated by Na, while the second is connected to an M+ center, possibly formed as result of the M center’s destruction by UV irradiation. The optically active centers in naturally irradiated fluorite responsible for red luminescence and purple color are different from one another. The most probable reason for the purple color is colloidal calcium and not the MNa center.

中文翻译：

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自然辐照萤石的红色光致发光和紫色

萤石的自然辐射诱导红色荧光由 750 和 635 nm 的两个宽带组成，衰减时间分别为 20.3 和小于 5 ns。第一个连接到由 Na 补偿的 M 中心，而第二个连接到 M+ 中心，可能是 M 中心被紫外线照射破坏的结果。自然辐照的萤石中负责红色发光和紫色发光的光学活性中心彼此不同。紫色最可能的原因是胶体钙而不是 MNa 中心。