This 8mm round features transparent glass encasing .925 sterling silver foil. The hole is approximately 1mm. These Authentic Murano Glass Beads are great for accents, wherever you need a small economical bead. . The sterling silver foil gives a brightness to the color. They are handmade and as such will vary in size. This bead is in Topaz medium color. The topaz is a bit darker in our sterling silver beads.)