Our sculpted opaque colors of black & aqua Murano Glass is hollow mouth blown Murano glass bead is the smaller approximately 20mm(+/- 2mm) size. The beads are blown and then after they have cooled are hand worked to grind the ridges in them. The shape is round. Sometimes the grinding goes through the glass, this is not a defect just how they are made and does not weaken the bead. They are little pieces are art no two alike.