The holes in these beads are lined with sterling silver and measure 4.5mm in diameter — that’s big enough to allow a 6:19 ring to pass through. I’ve been playing with a thin chain that slips through, and then enlarging the chain on both sides to trap the bead. The bead itself is roughly 13mm across and roughly 7mm high.
Please note: My supplier for these beads has apparently gone out of business. Once these beads are gone, they’re gone.