Natural stone-granite-is indeed 100% natural since it is quarried directly from the earth in large blocks. These blocks are then sliced into slabs and polished on one side at the quarry before being shipped to the broker or fabricator. Fabricators cut shapes from the slabs according to your countertop specifications. They then profile and polish the edges.
Quartz, on the other hand, is an “engineered” stone, meaning a manufacturing plant uses various grades and sizes of quartz crystals and mixes them with resin and pigment (for color) in a ratio of 93% quartz to 7% resin (yes, we’ll still refer to quartz as natural stone, but it’s not as natural as granite). Fabricators create quartz countertops in much the same way as they do granite countertops: by cutting the shapes from the slab and then profiling and polishing the edges