We picked this piece of crystallized quartz up from a rock hunting trip down in Dumfriesshire earilier in 2025. We have been lucky with the weather this year. Of three trips, only one was wet. We picked this one up in the wet. I remember thinking it wasn't a smoky quartz and that it was just wet. But it was a smoky quartz! It is just covered with that milky white layer of baryte. 
 
Of course we assumed it was calcite and, to be fair, it still might be. But there is so much weight in this rock that you wouldn't think was there. We put the extra weight down to barite. Again though, it might not be. There is something glinting on the underside of this rock. I would suspect copper but there is no visible greenery. At any rate, you get a mixed mineral and possibly a bonus of a rarer one than we know how to identify.