9mm I am selling items from my collection little by little to organize it. * To prevent any problems, please be sure to ask any questions you may have regarding the size of the beads, inner diameter, etc., before purchasing. Please note that you will not be able to confirm the details with the images after purchase. * There may be small chips, cracks, and scratches. Thank you for your understanding. #NaturalStone #NaturalStoneBracelet #Amethyst