Dark blue four-sided diamond beads

These are vintage German glass beads made between 1919 and 1938. The four-sided bead is indented and then the sides flare out to join with the next bead face. This effect of the softly contrasting strip with a sheen on top is one of my favorites. I love these beads and they have become impossible to get. The bead is 20 mm long and 10 mm wide. Each strand contains about 10 beads.