Nanodiamonds are diamonds whose size is of the scale of 4-5 nanometers. Nanodiamonds can be found inside meteorites. Nanodiamonds can be produced by impact events such as an explosion.
A single imperfection can give a nanodiamond an isolated color center, which lets it function as single, trapped atom. Relative to the defect size, they have huge surface areas that allow them to bond with a variety of other materials. Their non-toxicity means that nanodiamonds may be useful in biomedical and mechanical applications.[1]