It absolutely works on (most)
Keep the drill bit and the stone bead wet--I use an old tupperware
bowl filled with water and ream the bead under the water. If you
dry-ream the beads, you run more risk of shattering the stone and
also will wear the diamond coating off the bit much faster.
Sometimes the bead will still shatter, but most can be safely
reamed--it's just a tedious process. Unless my design really needs
a heavier wire, I'll usually try to work with a smaller gauge wire
to avoid reaming.
Also, some beads are just too big to be reamed out successfully,
since the bits are tapered. But most gem beads can be made to fit a
larger wire (or stringing medium) with a gentle hand and some