Sefer HaIkarim
A craftsman’s genius is two sided: one, is a great artist working with the best materials. A sight of the product shows the greatness of the artist. like beautiful gold and precious stone utensils, which undoubtedly show the work of a great artist.
However, a more sublime greatness is shown by one who makes beautiful utensils from ugly substances. The sight of iron utensils which are finely formed undoubtedly shows the smiths wisdom and perfection. This is because Iron is very difficult to work with. This craftsman is certainly better than he who works with fine product. … {when lower forms of creation are studied}, like molds, we see how G-d takes takes simple ingredients and gives them life.