december: orange moondust

Most moondust is very fine. This sample of orange soil, collected by geologist Harrison Schmitt during the Apollo 17 mission, was particularly so. The particles magnified here are between 20 and 45 microns (0.02 - 0.045 mm) across. The orange particles are similar to some of the samples from Apollo 11, being rich in titanium and iron oxide, but unusually are also rich in zinc. The orange soil is thought to be volcanic in origin.

Image: NASA.