At a friend's recommendation, we checked out the Tucson Gem and Mineral Show. We treated it like a giant natural history museum, but it's populated by an amazing subculture of people who are very into rocks. It's basically like the world of art collectors, but much, much nerdier.
Some observations:
Crinoid fossils are amazing! I didn't know these existed, and they're like H R Giger alien forms.
Things that have bony exoskeletons and live at the bottom of the sea fossilize really well. Consequently, there are a lot of them.
To me as an outsider, a lot of the prices made very little sense, and had little correlation to the aesthetic value of the mineral. I talked to a few people about this, and I think what's going on is that everyone's walking around with different value functions, and some of them are subtle and signal membership in a particular subculture. For example, pyrite is usually cubic, but on rare occasion it's hexagonal. To most people, both forms look similar, but to a pyrite-obsessed mineralogist, owning hexagonal pyrite is a rare specimen, and it shows you're in the know. Some crystals could be turned into precious gems, and that puts a flood on the price. If you're a seller, you're going to price everything at the highest price you can get for it, and that means that anything prized by a small subculture will be priced for that subculture, and mystifyingly expensive to everyone else. Sometimes, looking at a big case of crystal specimens arranged in a grid felt like I was seeing a set of NFTs.
Crystals in their raw form or semi-raw form look more compelling than in their "precious gem" cut / finished form. Basically, we're so good at creating perfect simulated gems out of glass and other materials that they're not that special anymore, but aesthetic science-museum hunks of rock are unique and draw more interest. Also, paradoxically, a necklace with a huge aquamarine gemstone actually looks cheap because my brain sees it and thinks "oh, that's huge, there's no way that's real so it's probably just glass"
There were a lot of amazing fossils, but we didn't buy any nice ones because it's really hard to spot fakes. As one point we were looking at a beautiful ichthyosaur fossil. The store owner came over and pointed out that it's actually composite of multiple fossil skeletons. This kind of spooked us, and we realized that we were way underqualified to make any high value purchasing decisions.
Addendum: Of course the crystal energy / crystal healing people are here. I find this hilarious because, if crystal energy actually worked, the size and density of crystals at the show would cause off-the-charts reactions. In some corners people would be leaping out of their wheelchairs and running across the room. In other areas, people would be unable to approach the crystals because anyone within a 10 foot range of them would simply fall asleep. It’s like the crystal energy version of walking around inside the core of a nuclear reactor.