this even possible (arch releated)

[jupiteran]

is it possible to get pristine solves from buying the fragments from the vendors instead of digging them up yourself.

[2about]

Yes.

/10char

[Delaios]

The crates contain the exact same fragments that you get from digging, they can even contain a keystone.

[Taalyn]

As far as I'm aware there aren't any special fragments that lead to a Pristine artifact. It's a % chance on every solve for the result to be Pristine.