Very difficult to find in quantitity other than singularly on mixed strands.
In Lewis and Clark's voyage of discovery, they mention somewhat in dismay, that the preferred bead by the locals was blue. Seems the East coast Indians liked red beads of which they had many, but they only had a few blue beads. It has been fairly well determined that the blue beads they carried were similar to small "padre" beads.
The larger "padre" beads where only given / traded to the "Chiefs" of a tribe ..
and that is where the name comes from. The blue chief’s beads, like chief’s blankets and chief’s guns etc., were always larger, prettier, or cost quite a bit more.
Many thanks to our customer / friend Steve in the USA for the above information.