It's certainly polycrystalline rather than a giant single-crystal. It would contain lots of every other element that's soluble in it, to its limit of solubilit

It's certainly polycrystalline rather than a giant single-crystal. It would contain lots of every other element that's soluble in it, to its limit of solubility, and whatever's insoluble or over that limit would have to form different mineral inclusions at grain boundaries.