Recommendation for a hand lens for a rough field environment/beginner?

I'm going to spend about a month outdoors in the Mojave. It's for some army training at a place called "The Box". It's very close to Death Valley. I've had to go there once before, and I remember there were so many cool rocks scattered everywhere. I didn't really know what I was looking at but I collected some cool pieces of quartz and pyrite. Lots of dried river beds and piles of mine tailings from the old gold mines that used to be active out there. It's very remote so there's some large specimens because the public can't access the area (it's a couple hundred square miles).

I'll have a lot of time just sitting around playing war out there, and I figured bringing a hand-lens out there this time could be a good way to nerd out and pass the time. Anyone have a recommendation for a good beginner hand lens that can survive being tossed in a ruck sack that'll probably be buried under a bunch of other gear? It's also very dusty out there so some kind of cover/cap is definitely mandatory.

Also if there are any good resources/field guides I could be pointed towards so I have a better idea of what to look for out there it would be very helpful. Thanks for any wisdom.