Thanks very much for that.

Quartz is a funny one. I've always felt drawn to it as well. Though this may just be the precious white shine of it, in comparison to the grey alternatives. The trouble with it, where we're concerned, is, if I may borrow one of Tiompan's phrases (;)), that it's so ubiquitous it would be hard to prove that its presence at monuments was always intentional, except if it could be proved, for example, to have come from some distance away.

I suspect that it may have meant different things in different areas. You coiuld make a good case for universal meaning where a type of architecture is concerned, (although even then, the variation in age and morphology between, say, types of stone circles would seem to put a stop to that run) but not a single type of stone.

Having said that, there has been research (and counter argument) into our reactions and, I think, the 'meanings' we may universally ascribe to different basic colours. I'd have to check this last sentence 'cos I'm working from memory.