I was sitting in a pub garden in Lacock, Wiltshire (where much of the Harry Potter films are made, and where photography was invented/developed in the Abbey), a few years ago, and there was a gravel floor to the garden. I noticed a half shell fossil, so I picked it up. On the top side was this perfect star - a plant segment which had stuck to the shell millions of years ago, had fossilised with it, then been dredged up for gravel. I found it by sheer chance. The actual shell it sits on is about three quarters of an inch long, so you can see how small the star is.
What a wonderful world.