This is an image from a diatom I have taken with a Scanning Electron Microscope.
Diatoms are singled celled eukaryotic, microscopic algae. Their uniqueness is that they spent their life enclosed in a cell wall which is made of silica, which is also called frustule. Amazingly, there is a huge diversity of shapes and ornamentations of the diatom frustule, and their pattern is characteristic for each species. Some features of the silica frustule can be only observed when magnified x5000 times or even more, with a Scanning Electron Microscope.
Not that they are just beautiful, but diatoms are also one of the most important and abundant algal groups. They live everywhere, where there is enough water; from freshwater lakes to the seas, from the Arctic ice to some hot springs. They are one of the most important primary producers in the freshwater and marine ecosystems. There are more than 100 000 species of diatoms.