Quilting cotton has a tighter weave and is slightly heavier than most apparel cottons. This density makes it stable for piecing, holds seams well, and withstands repeated washing. The tighter weave also means your needle makes clean holes rather than pushing threads aside. Apparel cottons like voile, lawn, and shirting are lighter and drape more softly, which is lovely for clothing but can shift and stretch during piecing. For quilt projects, stick with fabric labeled as quilting cotton.