At the same time as we find it occurring at Assiut, we also find the spiral used to decorate a scarab bearing the prenomen of Usertsen I (fig. 82). On this specimen the ornament is cut with very great care and regularity, indicating that the design was “a novelty, which had not yet become stereotyped[119] and reproduced as a matter of course.” The same exquisite workmanship is found on some scarabs bearing private names of the time of Amenemhat III or a little later; and here the continuous coil is combined with the lotus in a most beautiful design—a continuous coil, with flowers and buds in the spaces (Pl. XIV, figs. 21-26). It is difficult to believe that such a design sprang into being fully developed; but nothing has yet been found in Egypt at all like it of a period anterior to the Twelfth Dynasty; we must therefore search for the origin and development of the spiral motive in ornament elsewhere than in the Nile Valley. We do not yet know sufficiently the history of the Delta to say definitely that it did not originate there, but the probabilities are that we should look for its earliest employment and development outside the realm of Egypt.[120] However that may be, the spiral was one of the most important of the motives of the decorative art of the ancient world. From very ancient times it was largely used by the peoples of Western Asia and the Eastern Mediterranean, and in “the wake of early commerce it was spread afield to the Danubian basin, and thence in turn by the valley of the Elbe to the Amber coast of the North Sea; there to supply the Scandinavian Bronze Age population with their leading decorative designs. Adopted by the Celtic tribes in the Central European area, it took at a somewhat later date a westerly turn, reached Britain with the invading Belgae, and finally survived in Irish art.”[121] [Sidenote: Material. Hard stones, obsidian, etc.] Scarabs are made of all kinds of material, from the hardest obsidian and amethyst, to soft steatite and even wood. In all ages they were made of hard stones. Obsidian, spotted diorite, beryl, white quartz, hematite, amethyst, serpentine, green and red jasper, as well as red carnelians, lapis lazuli, and turquoise were all in use from the end of the Twelfth Dynasty onwards to the Twenty-sixth. Rarely during the earlier periods were the bases of the hardest stone specimens engraved; they were usually covered with a gold plate, upon which the device or inscription was incised. [Sidenote: Gold, silver, etc.] Metal scarabs are very rare: a few of gold, and two or three of silver are known of the Eighteenth and Nineteenth Dynasties, while about a dozen examples of bronze, of the Nineteenth and Twentieth Dynasties, are preserved in our museums. [Sidenote: Glass and cyanus.]