Preparation of natural diamonds by HPHT annealing of synthetic diamonds

In this paper, IIa, Ib, N-doped and N-H co-doped diamonds were studied, and the interaction mechanisms between hydrogen and nitrogen in the diamonds were investigated in detail. The results show that the degree of nitrogen aggregation in the {111} face is higher than that in the {100} face. The N-doped and N-H co-doped crystals exhibit an obvious color difference between the {100} and {111} faces within the same crystal after annealing. The existence of hydrogen is favorable for the aggregation of nitrogen atoms from C-centers to A-centers and B-centers in diamonds. By annealing N-H co-doped diamonds, hydrogen-doped IaA+B type synthetic natural diamonds were obtained.