Electron backscatter diffraction is a method that can visualise the orientation of crystals in a mineral, yielding beautiful stained glass-like pictures of biominerals. When it is used on sections of earthworm granules this is the result:
Electron Backscatter Diffraction (EBSD) orientation contrast map of an earthworm granule highlighting its polycrystalline microstructure. Image by Martin Lee, School of Geographical and Earth Sciences, University of Glasgow.
Silent witnesses 