Diamonds from the Mir Pipe (Yakutia): Spectroscopic Features and Annealing Studies

For this study, 21 samples of colorless octahedral diamonds (weighing 5.4–55.0 mg) from the Mir pipe (Yakutia) were investigated with photoluminescence (PL), infrared (IR), and electron paramagnetic resonance (EPR) spectroscopies. Based on IR data, three groups belonging to types IIa, IaAB, IaB selected their spectroscopic features analyzed in detail. The categories stones exhibited different characteristic PL systems. type demonstrated dominating nitrogen–nickel complexes S2, S3, 523 nm, while they less intensive or even absent IaAB crystals. IIa showed a double peak at 417.4 + 418.7 nm (the 418 center study), which is assumed be nickel–boron defect. In crystals analyzed, no matter type, 490.7, 563.5, 613, 676.3 systems various intensity could detected; moreover, N3, H3, H4 centers very common. step-by-step annealing experiments performed temperature range 600–1700 °C. treatment 600 °C resulted 563.5 system’s disappearance; interstitial carbon vacancy annihilation considered as reason. 676.5 613 defects annealed out 1500 1700 °C, respectively. Furthermore, result 558.5 576 superdeep São Luis (Brazil) appeared. These transformations explained by nitrogen diffusion interaction dislocations and/or vacancies produced.