I'm more of a folklorist than a stone head really, so I'm finding this very site educational. That plus I was brought up a pagan so I tend to look at things as a pagan would. It makes all the difference. For instance, I take people on the Winter Solstice torchlit parade every year on a storytelling session. There are always a few tourists that tag along with the group hoping you won't notice they didn't book, or thinking it's a free service as part of the entertainments. As there are 15,000 people in the parade, it's unlikely one storyteller would be enough, but anyway, my costume makes me stand out so they hang around to listen. You explain the birth of the child of light, and teach them the cries of Helya! (The Americans usually come out with Hell Yeah! instead, which is cute). It takes them ages to realise the child of light isn't Jesus, whereupon, some throw a fit. THATS when you point out it was made clear on the booking form and when they paid, that it was a pagan storyteller. LOL.
The thing about the Cailleach family in Glen Lyon is that local stories have it that they can look after themselves. Photos won't develop for some people. The stone family have been removed, only to mysteriously reappear. They sit in their hut, then move out to sit outside it, and no one sees the caretakers that move them, or rescue them from wherever they have been taken when they go missing. I grew up on remote farms and the caretakers used to be tough old shepherds, travellers, and the like.
I heard of a caretaker from Yorkshire who used to paint a stone white (which washed off easily in the next rainfall) once a year, without ever getting caught doing it. His family always farmed the land near there and had been doing it for forever, it seemed. Maybe it's the colour that is sacred. A white stone, from the black earth. All that's missing from the three sacred colours is the red, and the stones seem connected to sacrifice in a lot of stories so it might come from that.
One last wander, was about Diodorus Siculus, who, in the first century describes a method of "great antiquity" for mining gold. The part that is of most interest is one of the final stages. He describes the gold as being found in quartz rich veins. The broken and ground stone gravel is set on an inclined stone table, and water is fed either manually, or by diverting a stream, so that the gravel can be sorted to remove the gold content, a bit like panning for gold is done. Anyway, the water as it flowed away from the inclined stone table looked like a river of milk, because of all the ground quartz in it. The ancients sacrificed gold, and indeed silver, back to the sacred waters. This could be a case of giving back what was taken in times of great need. A realisation that they had taken too much and were now out of favour with the gods? Or an exercise in showing the gods their artistry in taking what the gods offered and turning it into something else before putting it back?
The river of milk, from the stone of quartz, that holds the shining gold and silver, might be represented by a large quartz stone, no? And could be where the ancients promulgated the goodwill of the gods who gave them the art of metallurgy, a craft that must have seemed magical. It would be interesting to know if the placement of those quartz stones happened in the begining of the metalworking era, when the craft was still seen as magical. From what I remember being told in school, gold was one of the first metals to be mined. It was easy to work, but had little practical value, so was seen as something mystical, of use only for religious or decorative purposes.
