Boy, am I lucky. I just returned from a week-long class at The Studio at The Corning Museum of Glass in Corning, New York. Davide Salvadore, a glass maestro from Murano, Italy, was teaching a course in murrine making, and how to pick them up on a blowpipe to make a piece out of it.
Murrine making is a technique that I use a lot, so it was a natural to take his class. He is a very generous man with his time and knowledge.
To make murrine, you bundle rods of color in a pattern that you choose, heat it all together, and then pull it like taffy, into a long, maybe 15 feet, rod. It then goes into the annealer, and the next day you slice it into 1/2" chunks. The cross-section pattern is what you're after.
I'll explain more and show some examples in later blog posts. Suffice it to say, the technique is tricky at first, but the patterns and combinations of colors are only restricted by your imagination, and Davide Salvadore is a master at this technique.