Soil minerals I now think is a more interesting topic. Most of us have more control over that than sunshine anyway. I've read many of the sempervivum-list.de descriptions by some of the big names over there and often it was mentioned that color was dependent on soil mineral content. No details provided of course.
Native soils in alpine (or desert) situations are quite "young" soils that have not been leached by rains for centuries like down here in the valleys. So mineral content may be more robust. Ph would also be slightly above neutral instead of below neutral like down here in the rain forests. That's why I've added a bit of Ca where I grow any succulents. I think it would be interesting to try some Ph experiments... why not. I think it may be time to break out that 50-pound bag of dolomite lime in my garden shed.
