Why hallo friend I would like a delightful headcannon on living aether please and thank you

This has taken an absurdly long time to answer because I ended up using this to refine some ideas I'd been tentatively poking at. :P

Anyway: DT'S LORECRAFTING AHOY.

So! Why is living aether, which by the very phrase is different from the ambient aether that's the normal background radiation of Etheirys, predominately found coalescing around pretty stones, like emeralds and topazes and rubies and diamonds?

Because rocks aren't alive.

Oh, sure, they still have aether in them, everything has aether in it, but stone doesn't have that tiny little spark that one day could become a soul. Now, something like a tree does, and if I may go off on a tangent for a little bit (nope, sorry, not actually a choice, you're getting a tangent) it's one reason that Urianger's amber carbuncle is such an impressive feat: amber that is magically conductive still retains the parent tree's unique aether, and it's not particularly keen on sharing with outside living aether or being anything other than a tree. Urianger had to build his arrays completely from scratch because he had to convince the aether in his piece of amber to be a carbuncle at all. Thus, an amber carbuncle, despite the similar appearance, is a very different type of construct compared to a traditional gemstone carbuncle with an affinity for earth aether: different sources of base aether.

Now, living aether that coalesces around stones aren't necessarily guaranteed to be carbuncles; more often than not, living aether is going to end up in a big chunk, spread across many stones, and end up very strongly aspected to earth, which results in earth elementals and golems (and possibly spriggans, although since it is unknown how that type of soulkin manifests, the matter is up for debate). Very rarely, living aether will instead end up highly concentrated in a single vein of a precious stone, and those cases, that living aether will always result in a carbuncle--but the carbuncle isn’t able to spontaneously manifest and is instead initially only able to manifest via summoning.

Now, why is that?

...Great question, I'm still figuring out the specifics of that and reserve the right to override anything posted here at a later date if I come up with a better system. :D Worldbuilding, always a work in progress!