The article describes the blue and iron ore from Sweden. According to David Olsen of Ingerborgs Stenar AB, a blue-patterned material known as Swedish Blue is cut from slag that was made during the Middle Ages until about 1865. The slag came from the silica-rich portions of the ore which floated to the surface. Meanwhile, the Swedish Iron Ore comes from a small mine near Nora. This mine is one of the few that produces a banded iron ore which is solid enough to cut and polish.