The crystallization step causes a loss of bead transparency (see Figure (b) inset): this is typical behavior for garnet vitroceramics, where large differences in density between glass and crystalline states cause fractures and pores to form upon crystallization. For compositions 0 ≤ x ≤ 0.5, the same crystallization products were obtained from powders and as-made beads, suggesting that surface crystallization is not dominant in this system. For compositions x > 0.5, high quality garnet samples could only be obtained by crystallizing bulk beads rather than powders, due to competition from surface crystallization of perovskite.