These little diamond tipped cutters are perfect. I am a mosaic artist and work almost exclusively with smalt, marble and ceramics. It may not be possible to get a clean edge in order for the pieces to fit together the way you want, and you don't rub these mosaics, leaving no room for error. I used a friend's desktop glass grinder and it was fine but very limited - I like moving around with my Dremel. Now I have the flex shaft and these bits and I'm really done. The speed of my projects has increased exponentially, which means ideas can flow faster and clients get their work on time and exactly how I envisioned it. These little pieces will be one of the staples in my tool box and you can't put ANY price on them! Even if I did a little a week it wouldn't matter - you can get that much for $14. Can't say enough good things about her. I needed them and finally they appeared.