This bead measures 4.5mm round. These are Bohemian glass beads with a wonderful green metallic finish. It's getting harder and harder to find this sort of finish on old nailhead beads these days. So I would say that this is a very rare finish. They are from the early 1900's. What a find! Glass nailhead beads were used in the days of the flapper to embellish garments before sequins were developed. You will receive 24 beautiful vintage beads per lot.