Borosilicate or "Boro", as it's usually called, is a harder glass and more difficult to work with, not to mention far more expensive. Generally a strand of boro beads can be anywhere from forty to more than two hundred dollars. It's a gorgeous glass and does the most unusual things and the things it does in the sunlight...well, you'll have to own one to find out. :) Boro bracelets begin at $169.99, unless you can catch a good sale.