In the following article, we have studied the variations of natural irradiation of diamond crystals. The natural diamonds in some cases show homogeneous green colour, caused by irradiation of the entire crystals volume. Radiation damage effects, produced by the low-radiation doses, are detected by the luminescence of the GR1 system. The high-radiation doses cause bluish hue, turning into a greenish colour, while the maximum level of volume irradiation produces the black crystals. The crystals with homogeneous volumetric black colour distribution were also studied. The major source of radiation in such cases may represent a local stream containing water rich in 222 Rn and its decay products. There is a review of the geological environment in which diamonds could be irradiated due to the decay of the 222 Rn containing in water.
Uralian, Anabar, and Brazilian diamond collections were studied by infrared spectrometry method. For reconstruction of thermal conditions of diamond formation were plotted Taylor Wayne diagrams with calculated isothermal curves. Diagrams of B2-defects distribution and H-centres were done. The conclusion about thermal formation conditions and possible belonging to the sea stream gravels were done.
