Gold particles

A picture from work. This shows dendrites of gold nanoparticles. The tree-like structures were formed when a homogeneous layer of nanoparticles were moved by the surface tension of an evaporating liquid. The picture was taken using dark field microscopy in polarised light. The shiny part up in the left corner are crystals of KCl. The whole image is about 1 mm across.
A bonus image below from another part of the sample.