we-are-star-stuff:

These are pollen grains captured under a Scanning Electron Microscope (SEM). What makes pollen so amazing, aside from making pretty microscopy pics and making people’s allergies play up? Pollen isn’t capable of dissolution in hydrochloric or hydrofluoric acids. What’s so amazing about that? Well hydrofluoric acid can break down silicic minerals and calcium – which includes human blood and tissue. HF can cause severe chemical burns and can be fatal. But it has no effect on pollen.
Palynology can be used to determine past environments and can be applied to problems in many fields including geology, botany, paleontology, archaeology, pedology (soil study), and geography.