A number of recovery experiments have been performed with bulk microcrystalline powder of w-ZnO under similar pressure-temperature conditions i.e., 7.7 GPa and 2000 K. Six representative experiments are described in Table . Three experiments (# 1, 2 and 3) were performed under triaxial compression in MA apparatus, and three others (# 4, 5 and 6) were performed under uniaxial compression in toroid-type apparatus. Experiments # 1 and 4 were performed with capsules of well-sintered pyrolytic BN ceramic (Saint-Gobain, AX05 grade); # 2 and 5 with capsules of compressed hBN powder (technical grade powder provided by the Institute for Superhard Materials, Ukraine); and # 3 and 6 without capsules, i.e. in MgO sleeve and directly in graphite heater, respectively.