One slab or two: when a kitchen island needs a seam
A kitchen island top in Asheville needs a seam only when it is longer or deeper than the slab it is cut from, so the size of the slab, not the size of the kitchen, decides the answer. One major quartz maker lists its original slabs at 56.5 by 120 inches and its jumbo slabs at 64.5 by 131.5 inches, and says the jumbo size exists largely to cut or remove seams on big islands.
That is why the island is often the one surface in the kitchen that can be seamless. Perimeter runs turn corners, meet the range and stop at the refrigerator, so they are cut in sections anyway. An island is a free-standing rectangle reached from every side, and if its footprint fits inside one slab it can come out of that slab whole.
Natural stone does not come in a catalog size. Every granite or quartzite block is sawn differently, so we measure the real slabs you are choosing between, not a brochure figure, before telling you whether the island fits in one piece.
When a seam cannot be avoided
An island longer than the longest slab gets a seam, and where it falls matters more than whether it exists. We keep it out of the seating zone and away from a sink or cooktop opening, and on a veined stone we place it where the pattern can run across the joint. You see that layout on the slab before the saw touches it.