Methods for making glass-ceramics comprising Al.sub.2O.sub.3, REO, at least one of ZrO.sub.2 or HfO.sub.2 and at least one of Nb.sub.2O.sub.5 or Ta.sub.2O.sub.5. Glass-ceramics according to the present invention can be made, formed as, or converted into glass beads, articles (e.g., plates), fibers, particles, and thin coatings. Some embodiments of glass-ceramic particles according to the present invention can be are particularly useful as abrasive particles.