Hole will take a 1mm thong. Price is for a pack of 10 beads.
A clay bead is formed and fired in a kiln. A coating of copper is applied to the clay base, then the bead is fired again. Finally a third layer of metal is applied, such as gold, silver or more copper , and the beads are kiln fired for a final time. This fuses the metal to the bead and makes the coating exceptionally hard-wearing. Many of the beads that I currently stock have large holes suitable for stringing on cord and leather thong. Naturally if they are placed next to an abrasive bead such as glass, some wearing will occur at the point of contact, but I have never seen the coating wear off next the skin unlike electroplated beads.
They will dull a little, over time on exposure to air, so I advise keeping them in sealed bags until needed for use. No abrasive products should be used on them, but a polish with a soft silver cloth helps to restore the shine.