I use a type of glass called Soda Lime Glass or Soft Glass. Most of it comes from Italy though some comes from China, USA and Germany.
The glass comes in rod form, pictured below.
I enjoy mixing different colours of glass to give interesting designs.
The matte finish on some of the beads is achieved by placing the beads in acid to etch them. I then neutralize and thoroughly clean all of the beads after this process.