Different materials come in different sizes. When countertops, islands and other pieces are longer than the slab, there will need to be a seam. When there are L shaped pieces, there is usually a seam on one side of the L joining the 2 pieces. Customers who have concerns about seam placement can discuss this with the salesperson. Seams in materials that have a pattern may not match. Book matching (where the material is colour and pattern matched) requires more material and will result in an increased cost.
Seams are typically 1/16” to 1/8” wide. Seams are cut on a CNC machine to make them as small and clean as possible. Although the seam is tight, it will still be visible.