Seal-cutter's trial-pieces present a rarity among Mesopotamian artifacts. To my knowledge the only example apart from the trial-pieces found by C. L. Woolley at Diqdiqqeh and Ur was for decades in a Swiss private collection and is now in the Vorderasiatisches Museum in Berlin (Figs. 4b and 5).

Though trial-pieces are, like moulds, engraved in intaglio they exhibit three distinct features: form, material and a lack of proficiency of many engravings (Figs. 1–5). Most have irregular contours and uneven surfaces; of the fourteen trial-pieces twelve are limestone or calcite and two potsherds. Although some surfaces are smoothed or polished, they show scratches and indentures, and one piece has a drill-hole on the roughly hewn back. The pieces look like leftovers from or parts of broken objects. Thus material for trial-pieces was only available in, or in proximity to workshops where leftovers from larger stone objects would be available to seal-cutters. Many figures on the trial-pieces demonstrate that the seal-cutter was not very accomplished (Figs. 1f, 2b, 3), two are skillfully executed by a master (Figs. 2a, 4a); most, however, are of average quality (Figs, 1a–d, 2c, 5), evidence for a workshop with masters and apprentices. The rarity of trial-pieces suggests that most seal-cutters trained on cylinders.

Of the provenanced trial-pieces all but one, which comes from the Gipar in Ur, were found at Diqdiqqeh. According to the excavators Diqdiqqeh, situated one mile south-east of the city wall of Ur, developed into an artisans' quarter starting with the Ur III period. The surface of this suburb was scattered with ruins of houses and numerous seals, terracottas, amulets and beads. Proportionally these were more numerous than at Ur, which could only be explained by the location of workshops in this area.