Yes, Tucson is a hub for gem sales and importing, partly due to the massive annual gem show, and partly because Arizona has a uniquely diverse selection of rockhounding and gem collecting opportunities due to its geology.
Gem collecting and/or being in a related business is not at all uncommon there, and for the most part pretty innocuous and unremarkable because it’s just a popular Arizona hobby. People like pretty and shiny things, and liking gems in Tucson is kind of liking cheese in Wisconsin.
Wholesalers tend to have a seasonal or year-round base there to sell to other businesses as well as individuals. Cash is of course a commonly welcomed payment, but I went to the shows multiple times a week this year and I didn’t see anyone at all who advertised or requested payment in bitcoin. I’m sure it happens, but it isn’t like some seedy market at the gem shows. It’s a big attraction for tourists as well as locals, from science enthusiasts to crystal healer types to jewelry makers and beyond.
I’m not aware of a gem robbery trend, though shops with big ticket specimens do take precautions, as you would expect for anywhere with pieces valued in the tens of thousands of dollars and up.
Jmo