Delica beads are small beads used for weaving and creating jewelry. They are uniform in size and shape so that they line up correctly when woven into jewelry. The beads have flat edges and a larger hole than typical seed beads to allow for several passes of thread.
Delica beads are made in Japan predominantly by three different companies. Matsuno Delica beads are the lowest quality available, being only slightly better than regular seed beads. Toho Delicas are mid-range beads. They are slightly more expensive and of better quality than those made by Matusno. According to Artbeads.com, delicas made by Miyuki are the highest quality of the three and are the most uniform in size and shape.