From at least the early 17th century to the latter part of the 18th century, drawn glass beads over about 4 mm in diameter were generally rounded in European glasshouses using a method called a speo by the Italians who apparently invented it. The little-known process involved mounting a number of tube segments on the tines of a multi-pronged iron implement which was then inserted in a furnace and turned until the tubes were rounded to the desired degree. Beads produced in this manner often exhibit distinctive characteristics and are easily identified in archaeological collections.
The Society of Bead Researchers is a non-profit scientific-educational corporation founded in 1981 to foster historical, archaeological, and material cultural research on beads and beadwork of all materials and periods, and to expedite the dissemination of the resultant knowledge. Membership is open to all persons involved in the study of beads, as well as those interested in keeping abreast of current trends in bead research.
"The A Speo Method of Heat Rounding Drawn Glass Beads and its Archaeological Manifestations."
BEADS: Journal of the Society of Bead Researchers
5: 27-36. Available at: