These unusual black glass beads are a rare style of Black Czech Bead. Prosser beads such as these are made by pressing glass in a mold to form a desired shape or pattern. These particular beads resemble a gear or the bark-like appearance of a plant and are a flat disk-like shape. Bead size can vary between 2-3mm wide and 7-9mm in diameter with a hole size of 1.5mm. Some strands may have up to 10% of other types of Prosser beads mixed in. Hard to find. Limited supply.