Biomineralization. Naturally aligned nanocrystals.

The aggregation of nanocrystals has long been believed to result in disordered solids. In his Perspective, Alivisatos discusses recent evidence that nanocrystals may also form oriented assemblies. He highlights the work by Banfield et al. in this issue, who show that such alignment can also occur in natural systems. The results may be of importance not only for geochemistry but also for the synthesis of advanced artificial materials.