Although people mistakenly call it “rod iron” or “rot iron,” the correct term is “wrought iron.” The word “wrought” comes from the verb “work”, wrought iron means “worked iron” or “forged iron”. Historically wrought iron has been worked by blacksmiths, using traditional techniques like hammers and anvils to make high end ‘Decorative Wrought Ironwork’.
Cast iron usually refers to grey cast iron. It tends to be brittle and hard on surface because of high carbon content (about 3% whereas 0.15% in wrought iron). Cast iron is made by remelting pig iron, often along with substantial quantities of scrap iron and scrap steel. After melting is complete, the molten iron is poured into shaping moulds. So once moulds is ready, mass production is possible.
The difference in quality and value is enormous although there is no visible difference to the naked eyes. Wrought iron is soft to forge or bend or weld, whereas cast iron is not. Cast iron is more fragile and easy to break, whereas wrought iron will bent rather than break. Besides, wrought iron can be welded and galvanized very easily, whereas cast iron cannot.