Prehnite bracelet with black tourmaline. It is said to be called tourmalinated prehnite. Inner diameter approximately 16cm (not measured accurately) Over 9mm. Brand new, unused. As it is a natural stone, there may be stone patterns or small scratches, please understand. I also have many other natural stones for sale. #IZUMI Natural Stone Please take a look here. We can ship multiple items together, so please feel free to contact us in the comments.