[Three Muses Glass]

Is that copper oxide? If so, cutting it heavily with clear frit, such as adding a small (very, very small) amount to some frit in a jar helps. Using it straight like that will most likely just get you black yuck. Using a small amount of that frit and encasing it with clear quickly will make pretty blue bubbles. I've used it for fusing, but the beads didn't turn out so well. If it's not copper oxide, never mind. lol
And it does get all over everything so contamination might be a problem.