Shimmering rounded growths of Smithsonite cluster on this specimen, layered atop of a plate of earlier Smithsonite and aurichalcite (perhaps intergrown). A bit of the original layer is exposed, and we can see the earlier Smithsonite is in the form of the rare "rice grain" crystals, and they are isolated on a matrix of aurichalcite-covered Smithsonite. The contrasts are subtle, and elegant. This is just an unusual specimen for the combination of styles, but it is pretty in its own right for the thick, translucent, very blue Smithsonite that is the core of the piece. From the Martin Zinn collection, specializing in New Mexico material over many years.