Cynthia, perhaps you weren't lubricating the stone. Usually water
is good enough, but keep more flowing while you're cutting. If it
still isn't working, send another posting.
Another thing about diamond drills and core drills, DON'T push
much pressure on them when drilling, you deplete the diamond
quickly that way and then it won't drill anymore. Keep it
lubricated at all time with water....DAve
Art Jewelry from Crystalguy, a Mineral Experience