Faience is a mixture of powdered clays and lime, soda and silica sand. Mix this with a little water to make a paste and molded around a small stick or bit of straw. Now it is ready to be fired into a bead. As the bead heats up the soda sand and lime melt into glass that incorporates and covers the clay. The result is a hard bead covered in bluish glass.
This process was probably discovered first in Mesopotamia and then imported to Egypt. But, it was the Egyptians who made it their own art form. Since before the 1st dynasty of Narmer(3100 B.C.) to the last dynasty of the Ptolomies(33 B.C.) and to the present day, faience beads have been made in the same way.
These beads predate glass beads and were probably a forerunner of glass making. If you are a little short of clay and have a little extra lime and the fire is hotter than usual, the mixture will become glass. In fact some early tubular faience beads are clayish at one end and pure glass at the other end. Apparently the beads weren't fired evenly.
The uneven beads were noticed early on, this led to experimentation, slowly at first. It took a long time for new ideas to be accepted in a conservative, agricultural society. One of the first variations to take hold was to color the faience beads by adding metallic salts. By the beginning of the eighteenth dynasty(1850 B.C.), faience making and glass making had become two separate crafts.
Faience beads were made in two basic shapes; flat discs and narrow cylinders. The sizes and colors may differ but these two shapes are found throughout the archaeological record from the earliest sites to the present day. Other common shapes include; the scarab beetle and melon shapes as well as specialty pieces for the ends of necklaces and bracelets.
Why were faience beads so common? They were cheaper and less labor intensive to make than stone beads. Aside from personal use and daily wear they were used to create beaded netting to cover mummies. Most of the archaeological specimens come from burials.
These beads were used to make elaborate beaded nets with intricate designs woven into the front across the breast or chest of the mummy. One such woven design is shown on page 42 of the "The History of Beads from 38,000 B.C. to the Present" by Lois Sherr Dubin. It is a winged scarab made of faience beads, and woven using a 2-drop peyote or gourd stitch. This was the central design of a netted shroud that covered the entire mummy. It may also be the earliest known use of peyote stitch. Faience beads were also incorporated into jewelry next to stone beads like lapis, turquoise, and carnelian as well as gold and silver beads and findings.