Kidney stone

Density-dependent colour scanning electron micrograph of the surface of a histological slide from a kidney stone (nephrolithiasis). Kidney stones form when salts, minerals and chemicals in the urine (for example calcium, oxalate and uric acid) crystallise and solidify. This dense, calcified material is visible here. Micrographs were coloured in post-processing by combining images acquired by two modes of image acquisition that use different kinds of electron microscope detectors. Colours relate to the different detectors and how they interact with the material. Horizontal width of image is 6.5 microns.