Smithsonite, from 79 Mine, Chilito, Hayden area, Banner Mining District, Gila County, Arizona, U.S.A. (REF:RSB25SM19)

Most Smithsonite is spherular, botryoidal, stalactitic, massive or earthy. Crystals are uncommon; they are prismatic, rhombohedral, or scalenohedral, and often have curved faces.

Smithsonite can be of various colours including yellow, orange, brown, pink, lilac, white, grey, green and blue. It forms oxidised zones of zinc deposits and in adjacent carbonate rocks. 

Very similar to  Hemimorphite, which can cause confusion.  Both minerals have been known by the term Calamine.