I am a stone beadmaker with 40 years experience and those , if they are stone , look exactly like chert. Chert is a type of jasper but of sedimentary not igneous origin. In the American Pacific north-west we have lots of very similar chert of oceanic origin , radiolarian chert. We seldom cut it because it all has very small blebs of random rocks in it just as your beads have. In the modern bead world the blebs keep the beads from selling despite the range of pleasant blues and greens of the chert.