Synthesis of spherical zinc oxide nanoparticles were successfully achieved by thermal annealing of hydrozincite (Zn5 (CO3) 2 (OH) 6) powder at 300oC in air for 1h. Zinc acetate dihydrate, Zn (CH3COO) 2. 2H2O was used as precursor with urea (NH2CONH 2) in 1: 4 molar ratio for the synthesis of hydrozincite by homogeneous chemical precipitation method under reflux for 1.5 h at 115oC. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) has been used to study the morphological features of the ZnO nanoparticles. X-ray powder diffraction (XRD) along with SEM and TEM indicated the sizes of as prepared ZnO nanoparticles to be 20-30 nm. Room temperature photoluminescence (PL) spectrum showed a strong band at 384 nm at 325nm excitation arising from recombination of free excitons indicating synthesized particles to be perfectly crystalline having low density of deep-level defects. A standard peak of zinc oxide was observed at 496 cm-1 from FT-IR spectroscopy.