depends on which stone you measure, but I've had it read anywhere from 3-3.4mm. very pretty beads, lots of flash in them. did get more peach on one strand than the other, which I was worried about from looking at the photos, so I bought two so I could even it out. all the way around, though, the cut us great, the quality of beads is high, and I'm pretty happy with these and will be ordering more.