Thanks Silken! And apologies to Pauline - I now see what you meant. The issue really is that the stone would be set upside down (if it were a cabochon) so I was hoping for at least a small table (as with the quartz in the photo, which isn't cabochon) and it rather depends how attractive the base of the cabochon is. These are great though - I can always order a few and see how they look. I can always set them right side up at a later date if they don't work for this project.
Bookmarks