In the third chapter of the manual, Theophilus gives detailed instructions on metalworking techniques. He explains how the workshop itself should be set up, then describes a variety of anvils used for different purposes, various sorts of hammers, rasps and files, chisels, pincers, chasing tools, scorpers, drawplates for making wire, and a special device called organarium for making beaded wire. Theophilus also explains how gold, silver, precious stones, and special decorative substances such as niello should be worked. Although this description dates from the twelfth century, most of the described techniques must have been still employed in the late Middle Ages. Unfortunately, no similar descriptions survive from later periods.
Archaeological evidence provides further information on medieval working procedures.
Sites with traces of the process of parting base metal from precious or gold from silver are sometimes found during excavations. Working tools and equipment, for example, hammers, moulds, crucibles, or the special vessel for separating gold from silver have also come to light. The workshops themselves rarely leave traces, as they were usually found within houses. Close examination of the surviving pieces, along with physical examination such as analysis of content, adds to our understanding of working techniques. Because of their small size, jewels were usually cast into shape with the cire perdue or lost wax technique.