Blue Berries
If the hematite had been vaporized by an asteroid impactor then it seems to me that it would form spheres as it condensed in the atmosphere and then rained back down onto the surface to be covered by sand and formed into the rocks sedimentary style.
On the other hand there is the possibility that molten hematite landed in water and created the round beads, that is how shot is made for blast hardening purposes.