Organic Solid hardwood flooring is a natural product and it will vary from texture, graining, knots, imperfections, and character. Fumed aging on oak products, over wood between boards, open & filled knots, splits & checks, ranging from large to small. Sticker marks & tannin-stains, heartwood and sapwood (light to dark) and varied texture due to custom 10 step proprietary process. Since this is a natural aspect of wood, it will create significant variation from plank to plank. Learn more here.