as i know they are falsely called donkey beads although you may find them easier when you call them that. in Iran the center of making these beads is Qom. it is said ancient Egypt and Persia were maker of these beads, but i heard in Mesopotamia they made it earlier. the turquoise color maybe is because of copper oxide using in glazing process. they have holes because they were used as button also i saw old carpets and nomad woven works with this bead in a corner, believing protection from evil eye. i remember 50 years ago all babies had this on their blouses. even goats and rams and donkeys horses, i had some with and without frames all late antiquity but color was changed a little. now a days people use them for decoration in Curtains also babies cloth.

hope this help you

Ali

At no time have I considered the possibility that these amulets are from ancient times. I have assumed they were probably under 100 years old. I have considered whether these particular ornaments, that I have assumed are Persian, were contemporaneous with the so-called "donkey beads" than have been commonplace over my entire career with beads, from the 1960s. But, perhaps surprisingly, in those early years I did not come across the disks. So I've been inclined to suspect they were probably somewhat older than the oblate beads that are much more common.

By the way, I have also seen non-faience imitations of these disk products, a very few times. I think I have one, somewhere.

Giorgio's short exposition is essentially a very quick rendering of the entire history of early faience, and doesn't address your actual question. However, I cannot disagree with what he says.

Jamey