The color of socks worn with jeans depends upon the shoes worn, not the pants, and it's influenced by the statement the wearer is trying to make. It is not necessary to match socks to pants.
When wearing a sneaker with jeans, wear athletic socks. Athletic socks should only be worn with athletic shoes. When wearing a dressier shoe with jeans, choose a dressier sock. A cotton sock may be worn with a casual shoe that is not a sneaker. Dress socks should not be worn with athletic shoes. A sock color may be chosen that complements the pant color or provides a pleasing contrast, but it is more important that the type of sock goes with the type of shoe worn.