The common feature of this group of images is some resemblance to flowers, plants or trees.

This feeling can often be perceived on a macroscopic scale, like with the well known “desert rose”, but it is also apparent in a microscopic view.
Flowers in this geologic greenhouse are quite small, down to less than a millimetre, and take up to hundreds million years to grow. But if we have the chance to get some, they may last forever, and do not need watering or fertilizer.