Ioffe Physical Technical Institute, 26 Polytechnicheskaya st. 194021, St. Petersburg, RussiaIt is well known that a commercial powder of detonation nanodiamonds (DND) and their aqueoussuspensions consist of agglomerates of 4 5 nm crystalline diamond grains. We have submitteda method for production of stable mono-disperse hydrosol of 4 nm isolated DND particles. Themethod includes deep puri“cation commercial DND from metal impurities and appropriate controlof its residual amount by electronic spin resonance, annealing of puri“ed DND in air and centrifu-gation. The main result of the study demonstrates that centrifuging of a DND hydrosol of particleswith a high negative zeta potential produced by deep puri“cation and air annealing results intobreakup of the agglomerates. A model explained high strength of the DND agglomerates has beendiscussed.