I used to own a small collection of pebbles that I’d gathered on my travels, each triggered fond memories of places visited. But all were left at my old place when I moved. For whatever reason I failed to start a new collection since moving. You’re right, I am drawn to the polished cobbles, some of them remind me of desert varnish. However if I could only pick one to place on my desk, then it would have be one of the small iron meteorites that have been spotted by the rovers. There are some nice SuperCam’s of this target, but my poor processing skills of those raw images don’t add any value