Well, given what I’ve seen so far it sort of seems to me like the gems, or at least the first one(s), were made by humans. There’s not really any other satisfactory way to explain why they look and function so similarly. Then I’d guess they were sent back in time via time magic, which we know is or at least was a possibility, and then eventually came to earth and disrupted their original timeline. I mean, I don’t think I’d hold onto that particularly hard, but I think that’s the theory that involves the fewest leaps of logic. I would be wiling to believe a natural formation if there had been any magic stuff since season one, but it’s trended in a more scifi direction since then.

