Snow cover crystals must be classified in a physically meaningful way. Previous classification systems are not sufficiently detailed or not based on sufficient knowledge of the physical processes. A new system is proposed based on our current knowledge of the physical processes of metamorphism. As more information about snow metamorphism is developed, the labels attached to snow grains should evolve too. Two levels of classification are proposed here. For practical purposes only a few terms like rounded and faceted are necessary, but for a more complete description a more detailed system is also given. The most basic description given in the table could be useful to many practitioners, while the more complete description given in the appendix will be necessary for many purposes.