We consider the problem of designing a lattice-based multiple description vector quantizer for a two-channel diversity system. The design of such a quantizer can be reduced to the problem of assigning pair labels to points of a vector quantizer codebook. A general labeling procedure based on the structure of the lattice is presented, along with detailed results for the hexagonal lattice: algorithms, asymptotic performance, and numerical simulations. Asymptotically, when compared with the lattice Z, the resulting quantizer achieves the standard second-moment gain of the hexagonal lattice for the central distortion, and, surprisingly, achieves the two-dimensional sphere gain for the side distortion.