Radiolaria

False coloured SEM of a radiolaria. Radiolaria are protozoa that have intricate mineral skeletons and are found throughout the ocean. Their skeletal remains often make up a large part of the ocean floor as siliceous ooze. Their fossilised skeletons have a characteristic structure and shape that can be used to date the age of the sedimentary rock. Horizontal field width is 239 microns. The sample was donated by Simon Crowhurst from the Department of Earth Sciences, Cambridge University, UK.