A while ago, I saw an interesting rock in some decorative gravel. I couldn't quite figure it out, so I cut it up and made a thin section. For those who don't know (probably most of you), a thin section is a slice of rock mounted on a microscope slide and ground down to 40 microns, or .001 inch. You can see all sorts of fascinating thing. Later I saw another interesting rock. That's the problem with being a geologist, EVERY rock is interesting. I made a thin section of that one, too. I kept seeing interesting rocks and making thin sections. I just realized I had put together a significant thin section collection. I even made thin sections out of some spare tektites I had (I found a very tiny bit of the original impactor in the Moldavite, and there was remnant structure in the Dainbai Indochinite). And I still have a bunch of rocks I haven't gotten to yet. I also have some fossils I may cut up to see the inside.
Some people say I'm nuts. They may be right.