“Diatoms are single cell algae that create jewel-like glass shells around themselves. Microscopists of the Victorian era would arrange them into complex patterns, invisible to the naked eye but spectacular when viewed under magnification.The best of these arrangements are stunning technical feats that reveal the hidden grandeur of some of the smallest organisms on Earth.”
I remember studying diatoms at university. They’re pretty fascinating things, and the different types of diatoms taken from, say, lake sediment can give an indicator as to what was happening to the land over time. They’re also rather pretty.