Multiple growth events in diamonds with cloudy microinclusions from the Mir kimberlite pipe: Evidence from the systematics of optically active defects

We present new data on the main and additional optically active defects in diamonds with cloudy microinclusions from the Mir kimberlite pipe. It has been found that reshaping might have occurred either in a closed system with nitrogen and hydrogen depletion or owing to new portions of a diamond-forming fluid/melt. The internal structure and the distribution of optically active defects suggest both continuous growth of such diamonds and a multistage scenario with a series of postcrystallizational transformations, including resorption, high-temperature annealing, and degradation of nickel-nitrogen complexes.